chore. update CHANGELOG

CHANGELOG

@@ -6,6 +6,7 @@
 - release 2.3.3-alpha.4 (remove deprecated native api)
 - release 2.3.3-alpha.5 (refactor event react api & refactor native wrapper)
 - release 2.3.3-alpha.6 (refactor with typescript & fix. iOS platform binding bug)
+- release 2.3.3-alpha.7 (refactor RtcEngine#init method support audio / video mode and switch dualStream)
 
 
 #### 1.1.2