Use Python 3.9 for build

Author: sliverc

.github/workflows/tests.yml

@@ -42,10 +42,10 @@ jobs:
         tox-env: ["black", "lint", "docs"]
     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 dependencies
         run: |
           python -m pip install --upgrade pip

.readthedocs.yaml

@@ -3,7 +3,7 @@ version: 2
 build:
   os: "ubuntu-22.04"
   tools:
-    python: "3.8"
+    python: "3.9"
 
 sphinx:
   configuration: docs/conf.py