diff --git a/.github/workflows/validation.yml b/.github/workflows/validation.yml
index dab16bf..10549bd 100644
--- a/.github/workflows/validation.yml
+++ b/.github/workflows/validation.yml
@@ -7,6 +7,7 @@ jobs:
     steps:
     - uses: actions/checkout@v2
       with:
+        ref: ${{ github.event.pull_request.head.sha }}
         fetch-depth: 0
     - name: Get changed files
       id: changed-files