Add license to files

src/main.jsx

@@ -1,11 +1,27 @@
-import React from 'react'
-import ReactDOM from 'react-dom'
-import './index.css'
-import App from './App'
+/*
+Copyright 2021 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import React from "react";
+import ReactDOM from "react-dom";
+import "./index.css";
+import App from "./App";
 
 ReactDOM.render(
   <React.StrictMode>
     <App />
   </React.StrictMode>,
-  document.getElementById('root')
-)
+  document.getElementById("root")
+);