chore: release 6.2.6 (#1443)

Prepare releasing **6.2.6**

After this pull request is merged, the following steps below will be
going on:

* Create tag for **6.2.6**
* Publish to pub.dev
* Create Github release for **6.2.6**

*This pull request is opened by bot*

Co-authored-by: littleGnAl <littleGnAl@users.noreply.github.com>

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## [6.2.6](https://github.com/AgoraIO-Extensions/Agora-Flutter-SDK/compare/6.2.4...6.2.6) (2023-11-21)
+
+
+### Features
+
+* upgrade native sdk 4.2.6 ([#1425](https://github.com/AgoraIO-Extensions/Agora-Flutter-SDK/issues/1425)) ([#1442](https://github.com/AgoraIO-Extensions/Agora-Flutter-SDK/issues/1442)) ([48b3dc4](https://github.com/AgoraIO-Extensions/Agora-Flutter-SDK/commit/48b3dc47c7d24f8dc2aacd371029cc7bc83baec9))
+
 ## [6.2.4](https://github.com/AgoraIO-Extensions/Agora-Flutter-SDK/compare/6.2.3...6.2.4) (2023-10-23)
 
 
@@ -125,4 +132,4 @@ feat: Convert kotlin to java to avoid kotlin version conflict
 
 See release note: 
 
-https://docs.agora.io/en/video-call-4.x-beta/release_flutter_ng?platform=Flutter
+https://docs.agora.io/en/video-call-4.x-beta/release_flutter_ng?platform=Flutter