Updated attribution

README.md

@@ -107,6 +107,7 @@ FairEmail uses:
 * [JCharset](http://www.freeutils.net/source/jcharset/). Copyright © 2005-2015 Amichai Rothman. [GNU General Public License](http://www.freeutils.net/source/jcharset/#license)
 * [Android Support Library](https://developer.android.com/tools/support-library/). Copyright (C) 2011 The Android Open Source Project. [Apache license](https://android.googlesource.com/platform/frameworks/support/+/master/LICENSE.txt).
 * [Android Architecture Components](https://developer.android.com/topic/libraries/architecture/). Copyright 2018 The Android Open Source Project, Inc. [Apache license](https://github.com/googlesamples/android-architecture-components/blob/master/LICENSE).
+* [colorpicker](https://android.googlesource.com/platform/frameworks/opt/colorpicker). Copyright (C) 2013 The Android Open Source Project. [Apache license](https://android.googlesource.com/platform/frameworks/opt/colorpicker/+/master/src/com/android/colorpicker/ColorPickerDialog.java).
 
 ## License