Python 3.13 instead of 3.7.

Author: eerimoq

.github/workflows/pythonpackage.yml

@@ -9,7 +9,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: [
-          '3.7', '3.8', '3.9', '3.10', '3.11', '3.12', 'pypy-3.8', 'pypy-3.9'
+          '3.8', '3.9', '3.10', '3.11', '3.12', '3.13', 'pypy-3.8', 'pypy-3.9'
         ]
     steps:
     - uses: actions/checkout@v4