Add php-cs-fixer action

Author: AlexVanderbist

.github/workflows/php-cs-fixer.yml

@@ -0,0 +1,23 @@
+name: Check & fix styling
+
+on: [push]
+
+jobs:
+    php-cs-fixer:
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout code
+              uses: actions/checkout@v2
+              with:
+                  ref: ${{ github.head_ref }}
+
+            - name: Run PHP CS Fixer
+              uses: docker://oskarstark/php-cs-fixer-ga
+              with:
+                  args: --config=.php_cs.dist --allow-risky=yes
+
+            - name: Commit changes
+              uses: stefanzweifel/git-auto-commit-action@v4
+              with:
+                  commit_message: Fix styling