fix(buttons): allow correct ref validation in PropTypes

Author: Austin Green

packages/buttons/src/views/icon-button/ChevronButton.js

@@ -46,7 +46,7 @@ ChevronButton.propTypes = {
   hovered: PropTypes.bool,
   active: PropTypes.bool,
   /** Callback for reference of the native button element */
-  buttonRef: PropTypes.func,
+  buttonRef: PropTypes.any,
   /** Rotates icon 180 degrees */
   rotated: PropTypes.bool
 };

packages/buttons/src/views/icon-button/IconButton.js

@@ -45,7 +45,7 @@ IconButton.propTypes = {
   hovered: PropTypes.bool,
   active: PropTypes.bool,
   /** Callback for reference of the native button element */
-  buttonRef: PropTypes.func
+  buttonRef: PropTypes.any
 };
 
 IconButton.defaultProps = {