Update dependencies

Author: bbc2

.github/workflows/main.yml

@@ -2,7 +2,7 @@ name: main
 on: [push]
 jobs:
   check-tests:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
     strategy:
       matrix:
         python-version: ['3.7', '3.11', 'pypy3.8']