Update changelog

Author: thomaskrause

CHANGELOG.md

@@ -3,6 +3,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.1.0] - 2022-06-01 
+
 - Update to graphANNIS 2.1.0 This does change the graphANNIS C-API (see
   <https://github.com/korpling/graphANNIS/blob/main/CHANGELOG.md#200---2022-03-29>)
   but does not actually the exported functions of the Python API.