Show a hint for the php-cs fix when the check fails

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

.github/workflows/lint.yml

@@ -33,4 +33,4 @@ jobs:
     - name: Install dependencies
       run: composer i
     - name: Run coding standards check
-      run: composer run cs:check
+      run: composer run cs:check || ( echo 'Please run `composer run cs:fix` to format your code' && exit 1 )