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

* Checked using https://github.com/myii/ssf-formula/pull/44

.travis.yml

 ---
 dist: bionic
 stages:
-  - test
   - lint
   - name: release
     if: branch = master AND type != pull_request
 
-sudo: required
-cache: bundler
-language: ruby
-
-services:
-  - docker
-
-# Make sure the instances listed below match up with
-# the `platforms` defined in `kitchen.yml`
-env:
-  matrix:
-    - INSTANCE: default-debian-10-develop-py3
-    # - INSTANCE: default-ubuntu-1804-develop-py3
-    # - INSTANCE: default-centos-7-develop-py3
-    # - INSTANCE: default-fedora-30-develop-py3
-    # - INSTANCE: default-opensuse-leap-15-develop-py3
-    # - INSTANCE: default-amazonlinux-2-develop-py2
-    # - INSTANCE: default-debian-9-2019-2-py3
-    - INSTANCE: default-ubuntu-1804-2019-2-py3
-    # - INSTANCE: default-centos-7-2019-2-py3
-    # - INSTANCE: default-fedora-30-2019-2-py3
-    # - INSTANCE: default-opensuse-leap-15-2019-2-py3
-    - INSTANCE: default-amazonlinux-2-2019-2-py2
-    # - INSTANCE: default-debian-9-2018-3-py2
-    # - INSTANCE: default-ubuntu-1604-2018-3-py2
-    # - INSTANCE: default-centos-7-2018-3-py2
-    - INSTANCE: default-fedora-29-2018-3-py2
-    - INSTANCE: default-opensuse-leap-15-2018-3-py2
-    # - INSTANCE: default-amazonlinux-2-2018-3-py2
-    # - INSTANCE: default-debian-8-2017-7-py2
-    # - INSTANCE: default-ubuntu-1604-2017-7-py2
-    - INSTANCE: default-centos-6-2017-7-py2
-    # - INSTANCE: default-fedora-29-2017-7-py2
-    # - INSTANCE: default-opensuse-leap-15-2017-7-py2
-    # - INSTANCE: default-amazonlinux-2-2017-7-py2
-
-script:
-  - bin/kitchen verify ${INSTANCE}
-
 jobs:
   include:
     # Define the `lint` stage (runs `yamllint` and `commitlint`)
       before_install: skip
       script:
         # Install and run `yamllint`
-        - pip install --user yamllint
-        # yamllint disable-line rule:line-length
-        - yamllint -s . .yamllint pillar.example pillar.debian.example
+        # Need at least `v1.17.0` for the `yaml-files` setting
+        - pip install --user yamllint>=1.17.0
+        - yamllint -s .
         # Install and run `commitlint`
         - npm install @commitlint/config-conventional -D
         - npm install @commitlint/travis-cli -D

.yamllint

 
 # Files to ignore completely
 # 1. All YAML files under directory `node_modules/`, introduced during the Travis run
+# 2. Any SLS files under directory `test/`, which are actually state files
 ignore: |
   node_modules/
+  test/**/states/**/*.sls
+
+yaml-files:
+  # Default settings
+  - '*.yaml'
+  - '*.yml'
+  - .yamllint
+  # SaltStack Formulas additional settings
+  - '*.example'
+  - test/**/*.sls
 
 rules:
+  empty-values:
+    forbid-in-block-mappings: true
+    forbid-in-flow-mappings: true
   line-length:
     # Increase from default of `80`
     # Based on https://github.com/PyCQA/flake8-bugbear#opinionated-warnings (`B950`)

kitchen.yml

 
 provisioner:
   name: salt_solo
-  log_level: info
+  log_level: debug
   salt_install: none
   require_chef: false
   formula: syslog_ng