Skip create PR when only git submodule is updated (#1210)

Even when only the submodule is updated and the code is not, a PR is
created in the bot SDK repository.(like
#1208)
If there is no diff in the generated code, I think it's sufficient for
Renovate to update the submodule version without creating a PR through
the GitHub Actions workflow.

Therefore, this change excludes the submodule from the PR creation
conditions and CI failure conditions.

Author: Yang-33

.github/workflows/generate-code.yml

@@ -25,7 +25,7 @@ jobs:
         id: setup_node_id
         with:
           node-version: 18
-      - name: actions/setup-java@v3
+      - name: Set up Java
         uses: actions/setup-java@3a4f6e1af504cf6a31855fa899c6aa5355ba6c12 # v4.7.0
         with:
           distribution: 'temurin'
@@ -39,8 +39,13 @@ jobs:
       - name: Generate code
         run: python3 generate-code.py
       - run: |
-          diff=$(git --no-pager diff --name-only)
-          echo "DIFF_IS_EMPTY=$([[ -z "$diff" ]] && echo 'true' || echo 'false')" >> $GITHUB_ENV
+          diff_files=$(git --no-pager diff --name-only)
+          diff_excluding_submodule=$(echo "$diff_files" | grep -v '^line-openapi$' || true)
+
+          echo "diff files: $diff_files"
+          echo "diff excluding submodule: $diff_excluding_submodule"
+
+          echo "DIFF_IS_EMPTY=$([[ -z "$diff_excluding_submodule" ]] && echo 'true' || echo 'false')" >> $GITHUB_ENV
           echo "CURRENT_DATETIME=$(date +'%Y%m%d%H%M%S')" >> $GITHUB_ENV
       ## Run if diff exists and pull request, and make CI status failure (but allow renovate bot)
       - if: ${{ github.event_name == 'pull_request' && env.DIFF_IS_EMPTY != 'true' && github.actor != 'renovate[bot]' }}