Fix GitHub Actions documentation update workflow push command

- Remove hardcoded repository URL from git push command
- Simplify push operation to use default remote repository

Author: Chivier

.github/workflows/update_docs.yml

@@ -47,4 +47,4 @@ jobs:
           git config user.name "Chivier"
           git config user.email "[email protected]"
           git commit -m 'update docs'
-          git push -u https://github.com/openmlsys/html-en.git main
+          git push