ci: generation job to follow conventional commit (#13846)

Author: suztomo

.github/workflows/codegen.yaml

@@ -40,8 +40,8 @@ jobs:
           upstream_owner: ${{ github.repository_owner }}
           upstream_repo: google-api-java-client-services
           description: 'Generated in GitHub action: https://github.com/${{ github.repository_owner }}/${{ github.repository }}/actions/workflows/codegen.yaml'
-          title: 'Regenerate ${{ matrix.service }} client'
-          message: 'Regenerate ${{ matrix.service }} client'
+          title: 'chore: regenerate ${{ matrix.service }} client'
+          message: 'chore: regenerate ${{ matrix.service }} client'
           branch: regenerate-${{ matrix.service }}
           git_dir: 'google-api-java-client-services/clients/google-api-services-${{ matrix.service }}'
           primary: main