fix(hooks): vm.$router should not be computed wrapper

Author: u3u

src/useRouter.ts

@@ -4,6 +4,5 @@ import { getRuntimeVM } from './util/runtime';
 export default function useRouter() {
   const vm = getRuntimeVM();
   const route = computed(() => vm.$route);
-  const router = computed(() => vm.$router);
-  return { route, router };
+  return { route, router: vm.$router };
 }