Early out of flake update if there are no changes (#192)

.github/workflows/commit.py

@@ -122,6 +122,8 @@ def create_pull_request(title: str, branch_name: str, base_branch: str) -> tuple
 
 def main():
     changed_files = get_git_diff()
+    if not changed_files:
+        return
 
     # Create blobs and prepare tree changes
     tree_changes = []

.github/workflows/flake_update.yaml

@@ -52,6 +52,7 @@ jobs:
         run: /tmp/venv/bin/python .github/workflows/commit.py
 
       - name: Enable Pull Request Automerge
+        if: ${{ steps.cpr.outputs.pull-request-number }}
         uses: peter-evans/enable-pull-request-automerge@v3
         with:
           token: ${{ steps.generate-token.outputs.token }}