Update bot_version for analytics plugin to 4.2.1

Signed-off-by: JordanP244656 <162927099+JordanP244656@users.noreply.github.com>

Author: JordanP244656

plugins/registry.json

@@ -120,7 +120,7 @@
         "repository": "JordanP244656/ModmailPlugins",
         "branch": "main",
         "description": "Simple analytics plugin for Modmail that tracks ticket activity and provides usage insights.",
-        "bot_version": "4.0.0",
+        "bot_version": "4.2.1",
         "title": "Analytics",
         "icon_url": "https://i.imgur.com/Mo60CdK.png",
         "thumbnail_url": "https://i.imgur.com/Mo60CdK.png"