chore(js-toolkit): make sure Lerna applies the right tag prefix for v2

Sadly, I can't know whether this tag prefix is going to be included in
the commit message or not (which might require changes to the "message"
config elsewhere in this file). I just have to try it and see what it
does.

maintenance/projects/js-toolkit/lerna.json

@@ -10,6 +10,7 @@
 	},
 	"npmClient": "yarn",
 	"packages": ["packages/*"],
+	"tagVersionPrefix": "liferay-js-toolkit/v",
 	"useWorkspaces": true,
 	"version": "2.19.3"
 }