inproper PropType warning for Icon's "name" prop

[neekey]

Hi, I am using semantic-ui-less to do style customization, and I changed the icon theme to material.

Since different icon sets have different class names, the type check for the name prop of Icon is no long proper for icon sets other than default.

Below is the warning I receive:

warning.js:36 Warning: Failed prop type: Invalid prop `name` of value `exit_to_app` supplied to `Icon`.