ci: trigger publish on tag push instead of release published

GitHub Actions does not fire workflow triggers for events created by
GITHUB_TOKEN, so the release-please bot creating a release never fired
the publish workflow. Switching to push: tags fires correctly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Chris1221

.github/workflows/python-publish.yml

@@ -2,8 +2,9 @@
 name: Publish to PyPI
 
 on:
-  release:
-    types: [published]
+  push:
+    tags:
+      - 'v*'
 
 permissions:
   contents: read