Revert ".github/workflows/test.yml: Add 3.13-dev"

This reverts commit dd059d8.

Author: mkoeppe

.github/workflows/test.yml

@@ -12,13 +12,11 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13-dev"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
         cython: ["cython", "cython<3.0.0"]
         exclude:
           - python-version: 3.12
             cython: cython<3.0.0
-          - python-version: 3.13-dev
-            cython: cython<3.0.0
     steps:
       - uses: actions/checkout@v2
         with: { submodules: recursive }