Update manifest for Gratrix.

manifests/Gratrix.json

@@ -3,5 +3,5 @@
   "author": "gratrix",
   "manualUrl": "http://gratrix.net/vcvrack/",
   "sourceUrl": "https://github.com/gratrix/vcv-gratrix",
-  "latestVersion": "0.5.0"
-}
+  "latestVersion": "0.6.0"
+}