Only try to commit if there are changes

Avoid failing workflow steps

Author: seaxwi

.github/workflows/deploy-prod.yml

@@ -32,5 +32,4 @@ jobs:
           git config user.name github-actions
           git config user.email github-actions@github.com
           git add .
-          git commit -m "Add article IDs to front matter"
-          git push
+          git diff-index --quiet HEAD || git commit -m "Update frontmatter" && git push