ci: stdlib: test again PYthon 3.11 dev

Author: scivision

.github/workflows/ci_stdlib_only.yml

@@ -17,7 +17,7 @@ jobs:
     name: ${{ matrix.os }} Python ${{ matrix.python-version }}
     strategy:
       matrix:
-        python-version: [ '3.7', '3.8', '3.9', '3.10' ]
+        python-version: [ '3.7', '3.8', '3.9', '3.10', '3.11-dev' ]
         os: [ 'ubuntu-latest', 'windows-latest', 'macos-latest']
 
     steps: