use precise imports of react-use

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

docs/tutorials/quickstart-app-plugin.md

@@ -135,7 +135,7 @@ changes, let's start by wiping this component clean.
 
 ```tsx
 import React from 'react';
-import { useAsync } from 'react-use';
+import useAsync from 'react-use/lib/useAsync';
 import Alert from '@material-ui/lab/Alert';
 import { Table, TableColumn, Progress } from '@backstage/core-components';
 import { githubAuthApiRef, useApi } from '@backstage/core-plugin-api';