Upgraded Python to 3.9 for PyPi CI deployment. Released v0.3.3.

Author: baochunli

.github/workflows/pypi_publish.yml

@@ -12,14 +12,14 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
-      - name: Set up Python 3.8
+      - name: Set up Python 3.9
         uses: actions/setup-python@v2
         with:
-          python-version: 3.8
+          python-version: 3.9
       - name: Install build dependencies
         run: |
           python -m pip install pip
-          pip install setuptools build wheel twine
+          pip install setuptools wheel twine
       - name: Build and publish
         env:
           TWINE_USERNAME: ${{ secrets.PYPI_USERNAME }}