Guard release and PyPI publish steps to only run on tag pushes

Both steps were running on workflow_dispatch from master where github.ref_name
is the branch name, not a version tag. This caused the release step to fail
which blocked the PyPI publish step entirely.

Author: maskedsyntax

.github/workflows/publish.yml

@@ -79,6 +79,7 @@ jobs:
           path: dist
 
       - name: Create GitHub Release
+        if: startsWith(github.ref, 'refs/tags/')
         uses: softprops/action-gh-release@v2
         with:
           files: dist/*
@@ -88,6 +89,7 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Publish to PyPI
+        if: startsWith(github.ref, 'refs/tags/')
         uses: pypa/gh-action-pypi-publish@release/v1
         with:
           verbose: true