diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 26de6a18..7e687195 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -92,6 +92,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
+        with:
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+          ref: ${{ github.event.pull_request.head.ref }}
       - name: Install php-cs-fixer
         run: composer global require friendsofphp/php-cs-fixer
       - name: Run php-cs-fixer