Fix branch typo.

Author: quebin31

.github/workflows/main.yml

@@ -67,7 +67,7 @@ jobs:
           git config --local user.email "quebin31@gmail.com"
           git config --local user.name "Kevin (CI/CD)"
           git commit -m "updver: $version" -a
-          git push origin HEAD:refs/head/master
+          git push origin HEAD:refs/heads/master
       - name: Publish to GitHub
         uses: softprops/action-gh-release@v1
         with: