Test python 3.12 and 3.13 (#211)

* fix error in readthedocs

* test up to python 3.13

Author: vuillaut

.github/workflows/continuousintegration.yml

@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.9, "3.10", "3.11"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
 
     steps:
     - uses: actions/checkout@v2