chore: 파일명 체크 방식에서 rebase가 필요하지 않도록 수정

Author: HC-kang

.github/workflows/integration.yaml

@@ -85,7 +85,9 @@ jobs:
       - name: Check filename rules
         if: ${{ steps.pr-labels.outputs.has_maintenance != 'true' }}
         run: |
-          files=$(git diff --name-only ${{ github.event.pull_request.base.sha }} ${{ github.event.pull_request.head.sha }} | tr -d '"')
+          # PR의 첫 커밋을 확인
+          merge_base=$(git merge-base ${{ github.event.pull_request.base.sha }} ${{ github.event.pull_request.head.sha }})
+          files=$(git diff --name-only $merge_base ${{ github.event.pull_request.head.sha }} | tr -d '"')
           pr_author="${{ github.event.pull_request.user.login }}"
           success=true