docs: import feathers-vuex

Author: marshallswain

docs/api-overview.md

@@ -100,6 +100,7 @@ import socketio from '@feathersjs/socketio-client'
 import auth from '@feathersjs/authentication-client'
 import io from 'socket.io-client'
 import { iff } from 'feathers-hooks-common'
+import feathersVuex from 'feathers-vuex'
 
 const socket = io('http://localhost:3030', {transports: ['websocket']})