Fix invalid reference to visualizeRevTree

We can now reference this directly from npm instead of resolving
from GitHub. The reference to GitHub was incorrect (referenced
non-existent gh-pages tag) which resulted in a resolution error
in the latest npm.

app/addons/documents/rev-browser/actions.js

@@ -13,7 +13,7 @@
 import FauxtonAPI from "../../../core/api";
 import {post} from "../../../core/ajax";
 import ActionTypes from "./actiontypes";
-import getTree from "visualizeRevTree/lib/getTree";
+import getTree from "visualize-rev-tree/lib/getTree";
 import PouchDB from "pouchdb-core";
 import PouchHttpAdapter from 'pouchdb-adapter-http';
 PouchDB.plugin(PouchHttpAdapter);

package.json

@@ -104,7 +104,7 @@
     "url-loader": "^2.0.1",
     "urls": "~0.0.3",
     "uuid": "^3.0.1",
-    "visualizeRevTree": "git+https://github.com/neojski/visualizeRevTree.git#gh-pages",
+    "visualize-rev-tree": "0.0.1",
     "webpack": "^4.41.0",
     "webpack-cli": "^3.3.9",
     "webpack-dev-server": "^3.8.2",