Update changelog

Author: frozzare

CHANGELOG.md

@@ -6,7 +6,7 @@
 * Fixed: Issues with color picker property that didn't work [#179](https://github.com/wp-papi/papi/issues/179).
 * Fixed: Editor tabs didn't work when flexible and repeater use `vertical` layout [#201](https://github.com/wp-papi/papi/issues/201).
 * Fixed: Remove duplicated database queries.
-* Fixed: `z-index` issue with flexible `add` button when placed under a editor [#198](https://github.com/wp-papi/papi/pull/198).
+* Fixed: `z-index` issue with flexible `add` button when placed under a editor [#198](https://github.com/wp-papi/papi/pull/198). Props [nlemoine](https://github.com/nlemoine).
 * Fixed: `nl2br` issue with text property [#199](https://github.com/wp-papi/papi/issues/199).
 
 ## [3.1.15](https://github.com/wp-papi/papi/releases/tag/v3.1.15) - 2016-10-06