fix(types): add typing for Routes meta (#89)

Add support for declaring the meta object in Nuxt.js Page, as we can see here https://github.com/nuxt/nuxt.js/tree/dev/examples/routes-meta 🤓 .

packages/types/app/vue.d.ts

@@ -20,6 +20,7 @@ declare module 'vue/types/options' {
     transition?: string | Transition | ((to: Route, from: Route) => string)
     validate?(ctx: Context): Promise<boolean> | boolean
     watchQuery?: boolean | string[]
+    meta?: { [key: string]: any }
   }
 }