update CHANGELOG

Author: maxulysse

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - [#614](https://github.com/SciLifeLab/Sarek/pull/614) - Add PR Template
 - [#615](https://github.com/SciLifeLab/Sarek/pull/615) - Add presentation
 - [#615](https://github.com/SciLifeLab/Sarek/pull/615) - Update documentation
+- [#620](https://github.com/SciLifeLab/Sarek/pull/620) - Add `tmp/` to `.gitignore`
 
 ### `Changed`
 - [#608](https://github.com/SciLifeLab/Sarek/pull/608) - Update Nextflow required version