Add pipeline-check for valid codestyle using php-cs-fixer

Author: Zombaya

.github/workflows/tests.yml

@@ -11,7 +11,7 @@ permissions:
   contents: read
 
 jobs:
-  run:
+  test:
     runs-on: ubuntu-18.04
     strategy:
       #for each of the following versions of PHP, with and without --prefer-lowest
@@ -86,3 +86,26 @@ jobs:
     - if: ${{ (matrix.php-versions == '7.1' || matrix.php-versions == '8.0') && matrix.composer-options == '' }}
       name: Code coverage
       run: bash <(curl -s https://codecov.io/bash)
+
+  lint:
+    runs-on: ubuntu-18.04
+    name: Lint
+    steps:
+      #sets up the correct version of PHP with necessary config options
+      - name: Setup PHP with Xdebug
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 8.1
+          ini-values: xdebug.overload_var_dump=0, memory_limit=4G, phar.readonly=false
+
+      #checkout the codebase from github
+      - name: Checkout codebase
+        uses: actions/checkout@v2
+
+      #get dependencies
+      - name: Install dependencies
+        run: composer update --working-dir=tools/php-cs-fixer --no-interaction
+
+      #run tests
+      - name: Lint codestyle using php-cs-fixer
+        run: tools/php-cs-fixer/vendor/bin/php-cs-fixer fix --verbose --dry-run