CI: Keep using Python 3.12 for PyPI test for now

This commit can be reverted once mypyc support Python 3.13

.github/workflows/pypi_upload.yml

@@ -73,7 +73,7 @@ jobs:
             | pyp 'json.dumps({"only": x, "os": "ubuntu-latest"})'
           } | pyp 'json.dumps(list(map(json.loads, lines)))' > /tmp/matrix
         env:
-          CIBW_BUILD: "cp38-* cp313-*"
+          CIBW_BUILD: "cp38-* cp312-*"
           CIBW_ARCHS_LINUX: x86_64
       - id: set-matrix
         run: echo "include=$(cat /tmp/matrix)" | tee -a $GITHUB_OUTPUT