Add 3.13 to test matrix as experimental

Author: toonarmycaptain

.github/workflows/CI.yml

@@ -13,10 +13,10 @@ jobs:
         python-version: ["3.10", "3.11", "3.12"]
         experimental: [false]  # These versions must pass.
 
-        # include:
-        #     - os: ubuntu-latest
-        #       python-version: 3.12-dev
-        #       experimental: true
+        include:
+            - os: ubuntu-latest
+              python-version: 3.13-dev
+              experimental: true
 
 #            - os: windows-latest
 #              python-version: 3.11-dev