(🎁) drop 'dev' from 3.12 in the CI (#16239)

Co-authored-by: KotlinIsland <[email protected]>

Author: KotlinIsland

.github/workflows/test.yml

@@ -64,7 +64,7 @@ jobs:
           tox_extra_args: "-n 2"
           test_mypyc: true
         - name: Test suite with py312-ubuntu, mypyc-compiled
-          python: '3.12-dev'
+          python: '3.12'
           arch: x64
           os: ubuntu-latest
           toxenv: py