chg: run GHA on more versions

Author: Rafiot

.github/workflows/mypy.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.10', '3.11', '3.12']
+        python-version: ['3.9', '3.10', '3.11', '3.12', '3.13']
     name: Python ${{ matrix.python-version }} sample
 
     steps: