publish.yml: only create release for tags (#40)

Author: ryan-williams

.github/workflows/publish.yml

@@ -27,6 +27,7 @@ jobs:
 
       - name: Create Release
         id: create_release
+        if: startsWith(github.ref, 'refs/tags/')
         uses: softprops/action-gh-release@v1
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}