Update CHANGELOG for release 1.1.0.

Author: marlycormar

CHANGELOG.md

@@ -2,6 +2,12 @@
 All notable changes to the REDCap CSS Injector module will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+
+## [1.1.0] - 2019-09-23
+### Added
+- Add flat/gradient stylized survey css example (Kyle Chesney)
+
+
 ## [1.0.1] - 2019-04-04
 ### Added
 - Add CSS Samples and 'Writing CSS for the CSS Injector' (Philip Chase)