License: adds license to Colored Radio

src/widgets/ColoredRadio.tsx

@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: © 2017 EteSync Authors
+// SPDX-License-Identifier: AGPL-3.0-only
+
 import * as React from 'react';
 
 import { makeStyles } from '@material-ui/core/styles';