Use react query on the login example

src/App.tsx

 import React from 'react';
 import { BrowserRouter as Router } from 'react-router-dom';
+import { ClientContextProvider } from './context';
 import { UserStateProvider } from './context/UserContext';
 import Routes from './Routes';
 
 function App(): React.ReactElement {
   return (
+    <ClientContextProvider>
       <UserStateProvider>
         <Router>
           <Routes />
         </Router>
       </UserStateProvider>
+    </ClientContextProvider>
   );
 }
 

src/hooks/useLogin.ts

+import { useMutation } from 'react-query';
+import useClientContext from './useClientContext';
+
+export default function useLogin() {
+  const client = useClientContext();
+
+  return useMutation('login', client.client.auth.login);
+}