Add explicit if statement to release only on publish

.github/workflows/release.yaml

@@ -132,7 +132,7 @@ jobs:
     name: release files to PyPI
     runs-on: ubuntu-latest
     # Protection Strategies -- use ONE of the following two lines:
-    # if: github.event_name == 'release' && github.event.action == 'published' # publish on via explicit publish
+    if: github.event_name == 'release' && github.event.action == 'published' # publish on via explicit publish
     # if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/v') # publish on tag starting w/ 'v'
     steps:
       - name: download files