use git to access changed files

.github/workflows/test-compat.yml

@@ -33,8 +33,10 @@ jobs:
     runs-on: ubuntu-latest
     if: ${{ github.event_name == 'pull_request' }}
     steps:
+      - name: Git diff
+        run: git diff --name-only -r HEAD^1 HEAD
       - name: Log changed files
-        run: echo "${{ toJSON(github.event.pull_request) }}"
+        run: echo "${{ contains(git diff --name-only -r HEAD^1 HEAD, 'libs/langchain-cohere') }}"
       # - uses: actions/checkout@v4
       # - name: Use Node.js ${{ env.NODE_VERSION }}
       #   uses: actions/setup-node@v3