fix(ci): upgrade Python to 3.9

.github/workflows/melpazoid.yml

@@ -11,9 +11,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Python 3.6
+    - name: Set up Python 3.9
       uses: actions/setup-python@v1
-      with: { python-version: 3.6 }
+      with: { python-version: 3.9 }
     - name: Install
       run: |
         python -m pip install --upgrade pip