👷 [github] Use Python 3.10 on Windows and macOS in Tests workflow (#664)

Author: cjolowicz

.github/workflows/tests.yml

@@ -22,8 +22,8 @@ jobs:
           - { python-version: 3.9, os: ubuntu-latest, session: "tests" }
           - { python-version: 3.8, os: ubuntu-latest, session: "tests" }
           - { python-version: 3.7, os: ubuntu-latest, session: "tests" }
-          - { python-version: 3.9, os: windows-latest, session: "tests" }
-          - { python-version: 3.9, os: macos-latest, session: "tests" }
+          - { python-version: "3.10", os: windows-latest, session: "tests" }
+          - { python-version: "3.10", os: macos-latest, session: "tests" }
           - { python-version: "3.10", os: ubuntu-latest, session: "typeguard" }
           - { python-version: "3.10", os: ubuntu-latest, session: "xdoctest" }
           - { python-version: "3.10", os: ubuntu-latest, session: "docs-build" }