renderdiff: add initial code for updating goldens (#8349)

- Code for parsing tag in commit message
- Add placeholder for pulling and updating goldens in the script.

.github/workflows/presubmit.yml

@@ -86,7 +86,7 @@ jobs:
       - uses: ./.github/actions/ubuntu-apt-add-src
       - name: Run script
         run: |
-          source ./build/linux/ci-common.sh && bash test/renderdiff_tests.sh
+          source ./build/linux/ci-common.sh && bash test/renderdiff/test.sh
       - uses: actions/upload-artifact@v4
         with:
           name: presubmit-renderdiff-result