fix(ci): do not run on py3.13 on mac

NEURON==8.2.6 isn't available

Author: sanjayankur31

.github/workflows/ci_versions.yml

@@ -17,7 +17,7 @@ jobs:
         runs-on: [ubuntu-latest, macos-latest, ubuntu-24.04 ]
         exclude:
           - runs-on: macos-latest
-            python-version: "3.9"
+            python-version: ["3.9", "3.13"]
 
     steps:
     - uses: actions/checkout@v4