(c) You must retain, in the Source form of any Derivative Works
that You distribute, all copyright, patent, trademark, and
attribution notices from the Source form of the Work,
excluding those notices that do not pertain to any part of
the Derivative Works; and
I understand that the icons are taken from Google's Material Design Icons? I believe these are under the Apache License, and the copyright notice needs to be preserved.
https://github.com/google/material-design-icons/blob/master/LICENSE#L101-L105