Update changelog

Author: shalvah

CHANGELOG.md

@@ -13,6 +13,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Removed
 
+## [3.9.0] - Saturday, 8 June 2019
+### Modified
+- Postman collections and URLs in example requests now use the `apidoc.base_url` config variable (https://github.com/mpociot/laravel-apidoc-generator/pull/523)
+
 ## [3.8.0] - Wednesday, 29 May 2019
 ### Added
 - Support for PHP array callable syntax in route action (https://github.com/mpociot/laravel-apidoc-generator/pull/516)