ci: push to fork instead of using access tokens

Author: quantum5

.github/workflows/update-versions.yml

@@ -31,3 +31,4 @@ jobs:
           body: This PR has been auto-generated to update the python versions in `build` action.
           reviewers: Xyene, quantum5, kiritofeng
           branch: update-versions
+          push-to-fork: dmoj-build/runtimes-python