Merge remote-tracking branch 'upstream/master' into generic-dataclasses

Author: dairiki

.github/workflows/python-package.yml

@@ -8,12 +8,16 @@ on: [push, pull_request]
 jobs:
   build:
 
-    runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
-        python_version: ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "pypy3.9"]
+        os: ["ubuntu-latest"]
+        python_version: ["3.7", "3.8", "3.9", "3.10", "3.11", "pypy3.9"]
+        include:
+          - os: "ubuntu-20.04"
+            python_version: "3.6"
 
+    runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}