add python 3.13 to CI

Author: Moritz-Alexander-Kern

.github/workflows/CI.yml

@@ -62,7 +62,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        # python versions for elephant: [3.8, 3.9, "3.10", 3.11, 3.12]
+        # python versions for elephant: [3.8, 3.9, "3.10", 3.11, 3.12, 3.13]
         python-version: [3.9, "3.10", 3.11, 3.12]
         # OS [ubuntu-latest, macos-latest, windows-latest]
         os: [ubuntu-latest]