fix: use the correct environment for uploading to pypi (googleapis#199)

Author: software-dov

.github/workflows/pypi-upload.yaml

@@ -7,6 +7,7 @@ on:
 jobs:
   publish:
     runs-on: ubuntu-latest
+    environment: PyPI
     steps:
     - uses: actions/checkout@v2
     - name: Set up Python