add licence to SynchronizableFileInfo.java

/* /e/ foundation Android Library is available under MIT license

 *   Copyright (C) 2019 Vincent Bourgmayer (/e/ foundation).

 *

 *   Permission is hereby granted, free of charge, to any person obtaining a copy

 *   of this software and associated documentation files (the "Software"), to deal

 *   in the Software without restriction, including without limitation the rights

 *   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 *   copies of the Software, and to permit persons to whom the Software is

 *   furnished to do so, subject to the following conditions:

 *

 *   The above copyright notice and this permission notice shall be included in

 *   all copies or substantial portions of the Software.

 *

 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

 *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

 *   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

 *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS

 *   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN

 *   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

 *   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 *   THE SOFTWARE.

 *

 */

package com.owncloud.android.lib.resources.files.model;

import android.support.annotation.NonNull;