Update changelog

Author: antonis

CHANGELOG.md

@@ -6,7 +6,7 @@
 > make sure you follow our [migration guide](https://docs.sentry.io/platforms/react-native/migration/) first.
 <!-- prettier-ignore-end -->
 
-## 6.8.0
+## Unreleased
 
 ### Features
 
@@ -20,6 +20,10 @@
   <FeedbackWidget/>
   ```
 
+## 6.8.0
+
+### Features
+
 - Adds Sentry Android Gradle Plugin as an experimental Expo plugin feature ([#4440](https://github.com/getsentry/sentry-react-native/pull/4440))
 
   To enable the plugin add the `enableAndroidGradlePlugin` in the `@sentry/react-native/expo` of the Expo application configuration.