Enable Python 3.13 for tests (#13)

Author: edenhaus

.github/workflows/ci.yaml

@@ -38,7 +38,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python: ["3.12"]
+        python: ["3.12", "3.13"]
     steps:
       - name: ⤵️ Check out code from GitHub
         uses: actions/[email protected]