improve deployment commits

.github/workflows/build.yaml

@@ -7,6 +7,13 @@ jobs:
     name: Build
     runs-on: ubuntu-latest
     steps:
+    - name: Set parameters
+      id: params
+      shell: bash
+      run: |
+        DATE_ISO=$(date --utc --iso)
+        echo "Setting parameter date_iso=$DATE_ISO"
+        echo "date_iso=$DATE_ISO" >> $GITHUB_OUTPUT
     - name: Checkout repository
       uses: actions/checkout@v4
     - name: Set up Python
@@ -26,3 +33,8 @@ jobs:
         github_token: ${{ secrets.GITHUB_TOKEN }}
         publish_dir: output
         publish_branch: gh-pages
+        full_commit_message: |
+          publish output on ${{ steps.params.outputs.date_iso }}
+          
+          code version ${{ github.sha }}
+          built by <${{ github.event.repository.html_url }}/actions/runs/${{ github.run_id }}>