Implement fork check for release task (#458)

Author: MattyTheHacker

.github/workflows/check-build-deploy.yaml

@@ -217,6 +217,9 @@ jobs:
               run: uv run -- ruff check --no-fix --output-format=github
 
     build-and-publish:
+        if: |
+            github.event_name != 'pull_request' ||
+            github.event.pull_request.head.repo.full_name == 'CSSUoB/TeX-Bot-Py-V2'
         runs-on: ubuntu-latest
         environment: publish
         needs: [mypy, pre-commit, prevent-migrations-deletion, pymarkdown, pytest, ruff-lint, uv-check]