Run release.yml on master and tags; only release on tags

Author: pjkundert

.github/workflows/release.yml

@@ -2,12 +2,13 @@ name: Release
 
 on:
   push:
+    branches:
+      - master
     tags:
       - '*'
 
 jobs:
   pypi-publish:
-    if: startsWith(github.ref, 'refs/tags')
     name: Upload release to PyPI
     runs-on: ubuntu-latest
     environment:
@@ -26,4 +27,5 @@ jobs:
         python -m pip install setuptools build
         python -m build -s
     - name: Publish package distributions to PyPI
+      if: startsWith(github.ref, 'refs/tags')
       uses: pypa/gh-action-pypi-publish@release/v1