Remove python 3.9

.github/workflows/python-package.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: [3.6, 3.7, 3.8]
 
     steps:
     - uses: actions/checkout@v2
@@ -24,6 +24,8 @@ jobs:
       uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python-version }}
+    - name: Display Python version
+        run: python -c "import sys; print(sys.version)"
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip