Add documentationUrl

CloudronManifest.json

@@ -38,5 +38,7 @@
     "https://s3.amazonaws.com/cloudron-app-screenshots/io.taiga.cloudronapp/9cd1802fd632d65ba2fff4fea32c2cb94a5a56a1/04.png",
     "https://s3.amazonaws.com/cloudron-app-screenshots/io.taiga.cloudronapp/9cd1802fd632d65ba2fff4fea32c2cb94a5a56a1/05.png"
   ],
-  "postInstallMessage": "file://POSTINSTALL.md"
+  "postInstallMessage": "file://POSTINSTALL.md",
+  "minBoxVersion": "1.8.1",
+  "documentationUrl": "https://cloudron.io/documentation/apps/taiga"
 }