Use cml to create/update PR comment

.github/workflows/dvc-diff.yml

@@ -54,7 +54,6 @@ jobs:
     - name: Generate the image diff report
       env:
         repo_token: ${{ secrets.GITHUB_TOKEN }}
-      id: image-diff
       run: |
         echo -e "## Summary of changed images\n" > report.md
         echo -e "This is an auto-generated report of images that have changed on the DVC remote\n" >> report.md
@@ -101,30 +100,5 @@ jobs:
         # Mention git commit SHA in the report
         echo -e "Report last updated at commit ${{ github.event.pull_request.head.sha }}" >> report.md
 
-        # Save the report content to the output parameter 'report'
-        echo 'report<<EOF' >> $GITHUB_OUTPUT
-        cat report.md >> $GITHUB_OUTPUT
-        echo 'EOF' >> $GITHUB_OUTPUT
-
-    - name: Find comment with image diff report
-      uses: peter-evans/[email protected]
-      id: fc
-      with:
-        issue-number: ${{ github.event.pull_request.number }}
-        comment-author: 'github-actions[bot]'
-        body-includes: 'This is an auto-generated report of images that have changed on the DVC remote'
-
-    - name: Create comment with image diff report
-      if: steps.fc.outputs.comment-id == ''
-      uses: peter-evans/[email protected]
-      with:
-        issue-number: ${{ github.event.pull_request.number }}
-        body: ${{ steps.image-diff.outputs.report }}
-
-    - name: Update comment with new image diff report
-      if: steps.fc.outputs.comment-id != ''
-      uses: peter-evans/[email protected]
-      with:
-        comment-id: ${{ steps.fc.outputs.comment-id }}
-        body: ${{ steps.image-diff.outputs.report }}
-        edit-mode: replace
+        # create/update PR comment
+        cml comment update report.md