Update pypi.yml

Author: harry093

.github/workflows/pypi.yml

@@ -22,7 +22,7 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v2
       with:
-        python-version: '3.7'
+        python-version: '3.8'
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip