added license to usage file

USAGE.md

@@ -205,6 +205,23 @@ Snapshots of the current development version of this library are available, whic
 Please contribute! We will gladly review any pull requests.
 Make sure to read the [Contributing](CONTRIBUTING.md) page first though.
 
+## License
+
+```
+Copyright 2020 The Android Open Source Project
+
+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
+
+    https://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
+limit
+
 [migratexmltocompose]: https://developer.android.com/jetpack/compose/designsystems/views-to-compose
 [compose]: https://developer.android.com/jetpack/compose
 [mdc]: https://github.com/material-components/material-components-android