ENH: Add update change log file to PR template checklist

Author: giovaniceotto

.github/pull_request_template.md

@@ -3,18 +3,21 @@
 <!-- You may use this template to describe your Pull Request. But if you believe there is a better way to express yourself, don't hesitate! -->
 
 ## Pull request type
+<!-- Remove unchecked box items. -->
 
 - [ ] Code changes (bugfix, features)
 - [ ] Code maintenance (refactoring, formatting, tests)
 - [ ] ReadMe, Docs and GitHub updates
 - [ ] Other (please describe):
 
 ## Checklist
+<!-- Remove irrelevant items to this PR. -->
 
 - [ ] Tests for the changes have been added (if needed)
 - [ ] Docs have been reviewed and added / updated
 - [ ] Lint (`black rocketpy/ tests/`) has passed locally 
 - [ ] All tests (`pytest --runslow`) have passed locally
+- [ ] `CHANGELOG.md` has been updated (if relevant)
 
 ## Current behavior
 <!-- Describe current behavior or link to an issue. -->
@@ -27,12 +30,12 @@ Enter text here...
 Enter text here...
 
 ## Breaking change
-<!-- If this introduces a breaking change, please describe the impact and migration path for existing applications below. -->
+<!-- If this introduces a breaking change, please describe the impact and migration path for existing applications below. Remove the unchecked box item. -->
 
 - [ ] Yes
 - [ ] No
 
 ## Additional information
-<!-- Include any relevant details or screenshots. -->
+<!-- Include any relevant details or screenshots. If none, remove this section. -->
 
 Enter text here...