Install pynn too

Author: pgleeson

.github/workflows/omv-ci.yml

@@ -41,6 +41,7 @@ jobs:
     - name: Regenerate
       run: |
         omv install pyNeuroML # required for regeneration (installs jnml too)...
+        omv install PyNN # required for regeneration...
         
         which pynml
         which jnml