Changelog entry for #558

Author: PragTob

CHANGELOG.md

@@ -5,6 +5,7 @@ Unreleased ([changes](https://github.com/colszowka/simplecov/compare/v0.13.0...m
 
 * Officially support JRuby 9.1+ going forward (should also work with previous releases). See [#547](https://github.com/colszowka/simplecov/pull/547) (ping @PragTob when encountering issues)
 * Add Channel group to Rails profile, when `ActionCable` is loaded. See [#492](https://github.com/colszowka/simplecov/pull/492) (thanks @BenMorganIO)
+* Stop `extend`ing instances of `Array` and `Hash` during merging results avoiding problems frozen results while manually merging results. See [#558](https://github.com/colszowka/simplecov/pull/558) (thanks @aroben)
 
 ## Bugfixes