Test on Python 3.10 (final).

Author: jaraco

.github/workflows/main.yml

@@ -9,8 +9,11 @@ jobs:
         python:
         - 3.6
         - 3.9
-        - 3.10.0-alpha - 3.10.99
-        platform: [ubuntu-latest, macos-latest, windows-latest]
+        - "3.10"
+        platform:
+        - ubuntu-latest
+        - macos-latest
+        - windows-latest
     runs-on: ${{ matrix.platform }}
     steps:
       - uses: actions/checkout@v2
@@ -34,7 +37,7 @@ jobs:
       - name: Setup Python
         uses: actions/setup-python@v2
         with:
-          python-version: 3.9
+          python-version: "3.10"
       - name: Install tox
         run: |
           python -m pip install tox