Bump test versions

Author: patrick-kidger

.github/workflows/run_tests.yml

@@ -7,7 +7,7 @@ jobs:
   run-tests:
     strategy:
       matrix:
-        python-version: [ 3.9, 3.11 ]
+        python-version: [ "3.10", "3.12" ]
         os: [ ubuntu-latest ]
       fail-fast: false
     runs-on: ${{ matrix.os }}