Add changelog entry

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [unreleased](https://github.com/mllam/weather-model-graphs/compare/v0.1.0...HEAD)
+
+### Added
+- added github pull-request template to ease contribution and review process
+  [\#18](https://github.com/mllam/weather-model-graphs/pull/18), @joeloskarsson
+
 ## [v0.1.0](https://github.com/mllam/weather-model-graphs/releases/tag/v0.1.0)
 
 First tagged release of `weather-model-graphs` which includes functionality to