Add entry

Author: compulim

CHANGELOG.md

@@ -144,6 +144,7 @@ Notes: web developers are advised to use [`~` (tilde range)](https://github.com/
       - `import { hooks } from 'botframework-webchat'` should be replaced by `import * as hooks from 'botframework-webchat/hook'`
    - Added target to Chrome 100 and re-enable Lightning CSS for ESM builds, by [@compulim](https://github.com/compulim) in PR [#5602](https://github.com/microsoft/BotFramework-WebChat/pull/5602)
 - Relaxed `role` prop to allow any string instead of ARIA landmark roles, in PR [#5561](https://github.com/microsoft/BotFramework-WebChat/pull/5561), by [@compulim](https://github.com/compulim)
+- Cleaned up `<ThemeProvider>` and various CSS related code, in PR [#5611](https://github.com/microsoft/BotFramework-WebChat/pull/5611), by [@compulim](https://github.com/compulim)
 
 ### Changed