Introduce stylelint to lint css / less files (#20926)

* Adds stylelinter as github action

* exclude stylelinter config file from builds

* exclude built vue files

* fix running stylelint

* Update .github/workflows/stylelinter.yml

Co-authored-by: Ben Burgess <[email protected]>

* restrict action permissions

---------

Co-authored-by: Ben Burgess <[email protected]>

.gitattributes

@@ -57,6 +57,7 @@ tests/ export-ignore
 .phpstorm.meta.php export-ignore
 .scrutinizer.yml export-ignore
 .travis.yml export-ignore
+.stylelintrc.json export-ignore
 PULL_REQUEST_TEMPLATE export-ignore
 
 # Linguist: language statistics

.github/scripts/clean-build.sh

@@ -225,6 +225,6 @@ for x in .gitignore .gitmodules .gitattributes .git-blame-ignore-revs .bowerrc .
     .phpstorm.meta.php .lfsconfig .travis.sh tsconfig.json tsconfig.spec.json \
     .eslintrc.js .eslintignore .eslintrc .browserslistrc babel.config.js jest.config.js \
     karma.conf.js karma-conf.js vue.config.js .npmignore .ncurc.json .prettierrc .jscsrc \
-    phpstan.neon phpstan.neon.dist package.xml; do
+    phpstan.neon phpstan.neon.dist package.xml .stylelintrc.json; do
     find . -name "$x" -exec rm -f {} \;
 done

.github/workflows/stylelinter.yml

@@ -0,0 +1,29 @@
+name: Stylelint
+
+on: pull_request
+
+permissions:
+  actions: none
+  checks: none
+  contents: none
+  deployments: none
+  issues: none
+  packages: none
+  pull-requests: read
+  repository-projects: none
+  security-events: none
+  statuses: none
+
+jobs:
+  phpcs:
+    name: stylelinter
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          lfs: false
+          persist-credentials: false
+      - name: stylelint
+        run: |
+          npm install
+          npx stylelint "**/*.{css,less}" -f github

.stylelintrc.json

@@ -0,0 +1,12 @@
+{
+    "overrides": [
+        {
+            "files": ["**/*.less"],
+            "customSyntax": "postcss-less"
+        }
+    ],
+    "ignoreFiles": ["node_modules/**/*", "vendor/**/*", "tests/**/*", "tmp/**/*", "misc/**/*", "plugins/*/vue/dist/*"],
+    "rules": {
+        "color-no-invalid-hex": true
+    }
+}