ci: enable Vagrant-based testing using GitHub Actions

Fix #495

* Semi-automated using https://github.com/myii/ssf-formula/pull/304

* Automated using https://github.com/myii/ssf-formula/pull/302

* Automated using https://github.com/myii/ssf-formula/pull/299

ci(windows): use `kitchen.windows.yml`

* Automated using https://github.com/myii/ssf-formula/pull/297

# [1.8.0](https://github.com/saltstack-formulas/salt-formula/compare/v1.7.5...v1.8.0) (2021-03-03)

### Features

* allow selecting alternate salt package repositories ([8742ab3](8742ab30bb))

### Tests

* **debian+ubuntu:** update `pkgrepo` to use `https` instead of `http` ([e94a8c9](e94a8c9dce))

feat: allow selecting alternate salt package repositories

```
$ GREP_SED="\(pkgrepo: deb http\):" \
  && grep -rl "${GREP_SED}" test/integration/v* \
     | xargs sed -i -e "/${GREP_SED}/s//\1s:/"
```

Make the upstream salt package repository selectable, thus allowing the
use of archived salt versions (hosted in
https://archive.repo.saltproject.io), as well as custom salt versions
hosted in alternate repositories.

## [1.7.5](https://github.com/saltstack-formulas/salt-formula/compare/v1.7.4...v1.7.5) (2021-03-02)

### Bug Fixes

* revert to using `is mapping` in Jinja2 ([a89fb3f](a89fb3f4aa))

### Continuous Integration

* **gemfile+lock:** use `ssf` customised `kitchen-docker` repo [skip ci] ([25fea89](25fea89238))
* **kitchen+gitlab-ci:** use latest pre-salted images [skip ci] ([fb9901e](fb9901e3ac))
* **pre-commit:** update hook for `rubocop` [skip ci] ([a874a76](a874a76967))

fix: revert to using `is mapping` in Jinja2

* CVE-2021-25283 enables Jinja2 safe mode, which breaks use of
  `'dict' in x.__class__.__name__` workaround
* Workaround no longer needed as CentOS 6 is EOL

* Automated using https://github.com/myii/ssf-formula/pull/296

* Automated using https://github.com/myii/ssf-formula/pull/295

* Automated using https://github.com/myii/ssf-formula/pull/294

* Automated using https://github.com/myii/ssf-formula/pull/293

* Automated using https://github.com/myii/ssf-formula/pull/292

* Automated using https://github.com/myii/ssf-formula/pull/290

## [1.7.4](https://github.com/saltstack-formulas/salt-formula/compare/v1.7.3...v1.7.4) (2021-01-29)

### Bug Fixes

* **osfamilymap:** update openSUSE `pkgrepo` URLs ([48f8da0](48f8da0357))
* **pkgrepo/suse/install:** avoid managing repo if it already exists ([d5320a3](d5320a35ed)), closes [/github.com/saltstack/salt/blob/45cc49daed1618dbe89e1f012128c8dcab00b356/salt/modules/zypperpkg.py#L1262-L1265](45cc49daed/salt/modules/zypperpkg.py/issues/L1262-L1265)

### Continuous Integration

* **kitchen+gitlab:** update for new pre-salted images ([a9413e8](a9413e8c29))

### Tests

* **tumbleweed:** add map verification files ([6aeaa5a](6aeaa5ac94))

ci(kitchen+gitlab): update for new pre-salted images

Use ugly `zypper lr --uri` hack to get around failure if the `base_url`
already exists under a different name:

```
      ID: salt-pkgrepo-install-saltstack-suse
Function: pkgrepo.managed
    Name: systemsmanagement_saltstack_products
  Result: False
 Comment: Failed to configure repo 'systemsmanagement_saltstack_products':
          Repository 'systemsmanagement_saltstack_products' already exists as 'systemsmanagement_saltstack'.
 Started: 09:28:39.154054
Duration: 2760.727 ms
```

Upstream code:

* 45cc49daed/salt/modules/zypperpkg.py (L1262-L1265)

* Semi-automated using https://github.com/myii/ssf-formula/pull/288

## [1.7.3](https://github.com/saltstack-formulas/salt-formula/compare/v1.7.2...v1.7.3) (2020-12-23)

### Tests

* **_mapdata:** generate verification files ([da6d150](da6d1509fd))
* **map:** verify `map.jinja` dump using `_mapdata` state ([d2404d5](d2404d5175))

test(map): verify `map.jinja` dump using `_mapdata` state

* Semi-automated using https://github.com/myii/ssf-formula/pull/285

## [1.7.2](https://github.com/saltstack-formulas/salt-formula/compare/v1.7.1...v1.7.2) (2020-12-20)

### Continuous Integration

* **commitlint:** ensure `upstream/master` uses main repo URL [skip ci] ([2a5b679](2a5b6798d4))
* **gitlab-ci:** add `rubocop` linter (with `allow_failure`) [skip ci] ([8417653](8417653525))
* **kitchen+gitlab:** adjust matrix to add `3002` ([7df2445](7df2445481))

### Tests

* **magnesium:** add pillar and tests for `3002` ([c066060](c0660608d7))

ci(kitchen+gitlab): adjust matrix to add `3002`

* Semi-automated using https://github.com/myii/ssf-formula/pull/280

* Automated using https://github.com/myii/ssf-formula/pull/278

* Automated using https://github.com/myii/ssf-formula/pull/277

## [1.7.1](https://github.com/saltstack-formulas/salt-formula/compare/v1.7.0...v1.7.1) (2020-12-16)

### Continuous Integration

* **gitlab-ci:** use GitLab CI as Travis CI replacement ([c9b2cb4](c9b2cb4a4a))

### Tests

* **fluorine:** remove pillar and tests for `2019.2` ([75ccf59](75ccf591eb))
* **pkgs_spec:** test for major version only (i.e. `3000`) ([618f95a](618f95a665))

* Automated using https://github.com/myii/ssf-formula/pull/275

* Automated using https://github.com/myii/ssf-formula/pull/274

* Automated using https://github.com/myii/ssf-formula/pull/273