message: Update changelog for test improvements
diff: * Improved diagnostics by refreshing them when the active editor changes or the current window is focused. (PR: [#2317](https://github.com/OmniSharp/omnisharp-vscode/pull/2317)) _(Contributed by [@SirIntruder](https://github.com/SirIntruder))
  +#### Testing
  +
  +* Improved the logs obtained when running or debugging tests using the codelens. (PR: [#2337](https://github.com/OmniSharp/omnisharp-vscode/pull/2337), [#2343](https://github.com/OmniSharp/omnisharp-vscode/pull/2343), [omnisharp-roslyn#1203](https://github.com/OmniSharp/omnisharp-roslyn/pull/1203))
  +
  ## 1.15.2 (May 15, 1018)
  * Fixed a 1.30.0 regression that prevented the script project system from working on Unix-based systems ([omnisharp-roslyn#1184](https://github.com/OmniSharp/omnisharp-roslyn/pull/1184), PR: [omnisharp-roslyn#1185](https://github.com/OmniSharp/omnisharp-roslyn/pull/1185)) _(Contributed by [@filipw](https://github.com/filipw))_
  