ci: deactivate coverage with xdebug

As coveralls is now deactivated for the time being, deactivating
xdebug should speed up the workflow.

.github/workflows/ci.yml

@@ -87,7 +87,7 @@ jobs:
         uses: shivammathur/setup-php@v2
         with:
           php-version: 8.2
-          coverage: xdebug
+#          coverage: xdebug
           extensions: mbstring
       - name: Get Composer Cache Directory
         id: composer-cache