Revert "Try using py3.12"

This reverts commit 4989adc.

Author: toomore

.github/workflows/pytest.yml

@@ -9,7 +9,7 @@ jobs:
     strategy:
       matrix:
         os: ["ubuntu-20.04"]
-        python-version: ["3.11", "3.12"]
+        python-version: ["3.11"]
     runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout