ci: lint pull request and YAML files (#2)

Makes sure to have valid pull request titles (for semantic versioning)
and valid YAML files.

Author: kayman-mk

.github/workflows/lint-files.yml

@@ -0,0 +1,13 @@
+---
+name: "Lint/Validate files"
+
+on: # yamllint disable-line rule:truthy
+  pull_request:
+
+jobs:
+  lint-yaml:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Validate YAML file
+        run: find . \( -name "*.yml" -o -name "*.yaml" \) | xargs yamllint -c .yamllint.yml --strict

.github/workflows/lint-pull-request.yml

@@ -0,0 +1,60 @@
+---
+name: "Lint Pull Request"
+
+on: # yamllint disable-line rule:truthy
+  pull_request_target:
+    types:
+      - opened
+      - edited
+      - synchronize
+
+jobs:
+  main:
+    name: Validate PR title
+    runs-on: ubuntu-latest
+    steps:
+      - uses: amannn/[email protected]
+        with:
+          # Default: https://github.com/commitizen/conventional-commit-types
+          types: |
+            build
+            chore
+            ci
+            docs
+            feat
+            fix
+            perf
+            refactor
+            revert
+            style
+            test
+          # Configure which scopes are allowed.
+          scopes: |
+            deps
+          # Configure that a scope must always be provided.
+          requireScope: false
+          # Configure additional validation for the subject based on a regex.
+          # This example ensures the subject doesn't start with an uppercase character.
+          subjectPattern: ^(?![A-Z]).+$
+          # If `subjectPattern` is configured, you can use this property to override
+          # the default error message that is shown when the pattern doesn't match.
+          # The variables `subject` and `title` can be used within the message.
+          subjectPatternError: |
+            The subject "{subject}" found in the pull request title "{title}"
+            didn't match the configured pattern. Please ensure that the subject
+            doesn't start with an uppercase character.
+          # For work-in-progress PRs you can typically use draft pull requests
+          # from GitHub. However, private repositories on the free plan don't have
+          # this option and therefore this action allows you to opt-in to using the
+          # special "[WIP]" prefix to indicate this state. This will avoid the
+          # validation of the PR title and the pull request checks remain pending.
+          # Note that a second check will be reported if this is enabled.
+          wip: true
+          # When using "Squash and merge" on a PR with only one commit, GitHub
+          # will suggest using that commit message instead of the PR title for the
+          # merge commit, and it's easy to commit this by mistake. Enable this option
+          # to also validate the commit message for one commit PRs.
+          validateSingleCommit: false
+          # Related to `validateSingleCommit` you can opt-in to validate that the PR
+          # title matches a single commit to avoid confusion.
+          validateSingleCommitMatchesPrTitle: false

.yamllint.yml

@@ -0,0 +1,10 @@
+---
+extends: default
+
+rules:
+  line-length:
+    max: 132
+    level: warning
+
+  comments:
+    min-spaces-from-content: 1

README.md

@@ -0,0 +1,4 @@
+## Workflows
+
+- lints all YAML files
+- lints the title of pull requests