Updated README to support new vue-router beforeRouteUpdate hook (#144)

Author: r4zzz4k

README.md

@@ -119,7 +119,8 @@ import Component from 'vue-class-component'
 // Register the router hooks with their names
 Component.registerHooks([
   'beforeRouteEnter',
-  'beforeRouteLeave'
+  'beforeRouteLeave',
+  'beforeRouteUpdate' // for vue-router 2.2+
 ])
 ```