Update Octopus AI prompt action to version 3

Author: mcasperson

step-templates/octopus-ai-prompt.json

@@ -3,7 +3,7 @@
   "Name": "Octopus - Prompt AI",
   "Description": "Prompt the Octopus AI service with a message and store the result in a variable. See https://octopus.com/docs/administration/copilot for more information.",
   "ActionType": "Octopus.Script",
-  "Version": 2,
+  "Version": 3,
   "CommunityActionTemplateId": null,
   "Packages": [],
   "GitDependencies": [],