Massively improve test suite coverage (#244)

Author: aik099

CHANGELOG.md

@@ -8,6 +8,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 ### Changed
 - The `Api::downloadAttachment` method now throws an exception, when attempting to download from a non-Jira website by [@aik099] (#240).
+- The `$params` argument of the `Api::getWorklogs` method is now optional by [@aik099] (#244).
+- The `$params` argument of the `Api::getTransitions` method is now optional by [@aik099] (#244).
 
 ### Removed
 ...