add contributors to the license
MIT License
-Copyright (c) 2019 LongYinan
-Copyright (c) 2019 Armin Sander
+Copyright (c) 2019 LongYinan & Armin Sander
+Copyright (c) 2019 rust-skia Contributors
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
