Allow finding external contributor's branch

Author: Ndpnt

.github/workflows/commit.yml

@@ -17,8 +17,10 @@ jobs:
           fetch-depth: 0
           ref: ${{ github.event.pull_request.base.ref }}
 
-      - name: Checkout the current pull request branch
-        run: git checkout ${{ github.event.pull_request.head.ref }}
+      - name: Checkout PR branch
+        run: |
+          git fetch --no-tags origin +refs/pull/${{ github.event.pull_request.number }}/head:${{ github.event.pull_request.head.ref }}
+          git checkout ${{ github.event.pull_request.head.ref }}
 
       - name: Install dependencies
         run: npm ci