Add copyright header into ContextUtils class

Summary: Trivial diff to include copyright header into ContextUtils class

Reviewed By: achen1

Differential Revision: D13001556

fbshipit-source-id: 439f25647a094485381637ea2b59f62962b9c1ac

Author: mdvacca

ReactAndroid/src/main/java/com/facebook/react/views/common/ContextUtils.java

@@ -1,3 +1,9 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
 package com.facebook.react.views.common;
 
 import android.content.Context;