Update changelog

Author: olgabrani

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - OpenAIRE
   - OpenMinTeD
 - Add info about compatiblity in README.
+- Enable/disable cookie banner functionality via setting in config file.
 
 
 ## [v2.1.0](https://github.com/rciam/simplesamlphp-module-themevanilla/compare/v2.0.0...v2.1.0) - 2018-10-18