ci: merge travis matrix, add `salt-lint` & `rubocop` to `lint` job

* Semi-automated using https://github.com/myii/ssf-formula/pull/60

```bash
Examining ufw/config/services.sls of type state
[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/services.sls:32
ufw-svc-{{method}}-{{service_name}}-{{from_addr}}:

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/services.sls:33
  ufw.{{method}}:

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/services.sls:35
    - protocol: {{protocol}}

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/services.sls:38
    - from_addr: {{from_addr}}

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/services.sls:41
    - from_port: "{{from_port}}"

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/services.sls:44
    - to_addr: {{to_addr}}

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/services.sls:49
    - comment: '"{{comment}}"'

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/services.sls:51
    - to_port: "{{to_port}}"
```

```bash
Examining ufw/config/open.sls of type state
[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/open.sls:20
ufw-open-{{open_addr}}:

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/open.sls:22
    - from_addr: {{open_addr}}

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/open.sls:24
    - comment: '"{{comment}}"'
```

```bash
Examining ufw/config/interfaces.sls of type state
[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/interfaces.sls:20
ufw-interface-{{interface_name}}:

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/interfaces.sls:22
    - interface: {{interface_name}}

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/interfaces.sls:24
    - comment: '"{{comment}}"'
```

```bash
Examining ufw/config/applications.sls of type state
[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/applications.sls:30
ufw-app-{{method}}-{{app_name}}-{{from_addr}}:

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/applications.sls:32
ufw-app-{{method}}-{{app_name}}:

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/applications.sls:34
  ufw.{{method}}:

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/applications.sls:35
    - app: '"{{app_name}}"'

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/applications.sls:37
    - from_addr: {{from_addr}}

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/applications.sls:40
    - to_addr: {{to_addr}}

[206] Jinja variables should have spaces before and after: {{ var_name }}
ufw/config/applications.sls:45
    - comment: '"{{comment}}"'
```

* Automated using https://github.com/myii/ssf-formula/pull/59

* Automated using https://github.com/myii/ssf-formula/pull/58

* Automated using https://github.com/myii/ssf-formula/pull/53

* Automated using https://github.com/myii/ssf-formula/pull/52

* Automated using https://github.com/myii/ssf-formula/pull/48

ci(platform): add `arch-base-latest`

* Automated using https://github.com/myii/ssf-formula/pull/41

* Automated using https://github.com/myii/ssf-formula/pull/40

ci(yamllint): add rule `empty-values` & use new `yaml-files` setting

* Automated using https://github.com/myii/ssf-formula/pull/27

ci(kitchen+travis): replace EOL images & apply `opensuse-leap-15` SCP error workaround

* Automated using https://github.com/myii/ssf-formula/pull/22

* Automated using https://github.com/myii/ssf-formula/pull/23

## [0.5.1](https://github.com/saltstack-formulas/ufw-formula/compare/v0.5.0...v0.5.1) (2019-08-25)

### Documentation

* **readme:** update testing section ([80a3734](https://github.com/saltstack-formulas/ufw-formula/commit/80a3734))

docs(readme): update testing section

chore: use `semantic-release` cross-formula standard structure

* Automated using `ssf-formula` (v0.6.0)

# [0.5.0](https://github.com/saltstack-formulas/ufw-formula/compare/v0.4.1...v0.5.0) (2019-08-17)

### Features

* **yamllint:** include for this repo and apply rules throughout ([38eb4dc](https://github.com/saltstack-formulas/ufw-formula/commit/38eb4dc))

feat(yamllint): include for this repo and apply rules throughout

* Semi-automated using `ssf-formula` (v0.5.0)
* Fix errors shown below:

```bash
ufw-formula$ $(grep "\- yamllint" .travis.yml | sed -e "s:^\s\+-\s\(.*\):\1:")
pillar.example
  1:1       warning  missing document start "---"  (document-start)
  3:12      warning  truthy value should be one of [false, true]  (truthy)
  7:11      warning  truthy value should be one of [false, true]  (truthy)
  12:22     warning  truthy value should be one of [false, true]  (truthy)
  64:13     warning  truthy value should be one of [false, true]  (truthy)
  69:13     warning  truthy value should be one of [false, true]  (truthy)
  77:13     warning  truthy value should be one of [false, true]  (truthy)
  84:14     warning  truthy value should be one of [false, true]  (truthy)
  101:16    warning  truthy value should be one of [false, true]  (truthy)
  106:14    warning  truthy value should be one of [false, true]  (truthy)
  110:13    warning  truthy value should be one of [false, true]  (truthy)

test/salt/pillar/default.sls
  1:1       warning  missing document start "---"  (document-start)
  2:12      warning  truthy value should be one of [false, true]  (truthy)
  9:14      warning  truthy value should be one of [false, true]  (truthy)
  12:13     warning  truthy value should be one of [false, true]  (truthy)
  15:13     warning  truthy value should be one of [false, true]  (truthy)
  19:13     warning  truthy value should be one of [false, true]  (truthy)
  25:14     warning  truthy value should be one of [false, true]  (truthy)
  29:13     warning  truthy value should be one of [false, true]  (truthy)
```

chore: use `semantic-release` cross-formula standard structure

* Automated using `ssf-formula` (v0.1.0-rc.2)

chore: use `semantic-release` cross-formula standard structure

* Automated using `ssf-formula` (v0.1.0-rc.1)

## [0.4.1](https://github.com/saltstack-formulas/ufw-formula/compare/v0.4.0...v0.4.1) (2019-07-13)

### Code Refactoring

* **kitchen+inspec:** move inline pillar to file ([0005375](https://github.com/saltstack-formulas/ufw-formula/commit/0005375))

### Continuous Integration

* **kitchen+travis:** modify matrix to include `develop` platform ([8699e9d](https://github.com/saltstack-formulas/ufw-formula/commit/8699e9d))

refactor(kitchen+inspec): move inline pillar to file

ci(kitchen+travis): modify matrix to include `develop` platform

* Use balanced matrix based on `template-formula` guidelines
* Initial ref: https://github.com/saltstack-formulas/template-formula/issues/118

# [0.4.0](https://github.com/saltstack-formulas/ufw-formula/compare/v0.3.0...v0.4.0) (2019-05-21)

### Continuous Integration

* **kitchen+travis:** test with pre-salted Docker images ([f27ec2e](https://github.com/saltstack-formulas/ufw-formula/commit/f27ec2e))

### Features

* **tofs:** switch to tofs ([c05019a](https://github.com/saltstack-formulas/ufw-formula/commit/c05019a))

Add tofs, use pre-salted images

# [0.3.0](https://github.com/saltstack-formulas/ufw-formula/compare/v0.2.0...v0.3.0) (2019-05-14)

### Continuous Integration

* **kitchen:** rename Kitchen config file ([2e59df4](https://github.com/saltstack-formulas/ufw-formula/commit/2e59df4))

### Features

* **semantic-release:** implement an automated changelog ([f25b404](https://github.com/saltstack-formulas/ufw-formula/commit/f25b404))

feat(semantic-release): implement an automated changelog

Allow multiple configurations for the same port

Also perform tests on bionic/18.04