Update main.yml

Author: MacHu-GWU

.github/workflows/main.yml

@@ -54,7 +54,7 @@ jobs:
       # don't forget to goto codecov.io, enable your repo, copy the token
       # create an CODECOV_TOKEN env var in GitHub actions secret
       - name: "Upload coverage to Codecov"
-        if: "${{ contains(env.USING_COVERAGE, matrix.python-version) && github.ref == 'refs/heads/main' }}"
+        if: "${{ contains(env.USING_COVERAGE, matrix.python-version) && github.ref == 'refs/heads/master' }}"
         uses: "codecov/codecov-action@v4" # https://github.com/marketplace/actions/codecov
         with:
           token: ${{ secrets.CODECOV_TOKEN }}