Update Python version matrix in CI workflow

Author: pgleeson

.github/workflows/omv-ci.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [ "3.10", "3.11", "3.13" ]
+        python-version: [ "3.10", "3.12", "3.13" ]
         engine: [ jNeuroML_validate, Brian2 ]
 
     steps: