Revert "Remove PHPCS config"

This reverts commit 8222cd5e9b.

.github/workflows/ci.yml

@@ -43,6 +43,12 @@ jobs:
         composer install --prefer-dist --no-suggest --no-progress --no-ansi --no-interaction
         echo "${PWD}/mu-plugins/vendor/bin" >> $GITHUB_PATH
 
+    - name: Run PHPCS on changed files
+      run: |
+        touch $GITHUB_WORKSPACE/tmp.php
+        export CHANGED_FILES=$(git diff --name-only --diff-filter=AM remotes/origin/${{ github.base_ref }} | tr '\n' ' ')
+        phpcs -q -n --report=checkstyle $GITHUB_WORKSPACE/tmp.php $(echo $CHANGED_FILES) | cs2pr
+
   phpunit:
     name: PHP Unit Tests