Merge pull request #5084 from github/copilot/fix-rubocop-checkout-branch

Fix lint workflow to checkout PR branch instead of base branch

Author: ahpook

.github/workflows/lint.yml

@@ -14,6 +14,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v6.0.1
+        with:
+          ref: ${{ github.event.pull_request.head.ref || github.ref }}
 
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1.284.0