chore(release): Prepare version 2.1.0

Author: dborsatto

CHANGELOG.md

@@ -3,7 +3,11 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
-## [Unreleased](https://github.com/contentful/contentful-core.php/compare/2.0.0...HEAD)
+## [2.1.0](https://github.com/contentful/contentful-core.php/tree/2.1.0) (2018-11-07)
+
+### Added
+
+* Interface `LinkResolverInterface` now declares method `resolveLinkCollection`.
 
 ## [2.0.0](https://github.com/contentful/contentful-core.php/tree/2.0.0) (2018-10-30)