chore. update changelog

CHANGELOG

 ## THE CHANGELOG
 
+#### 2.9.0-alpha.2
+  - fix ios dictionary stringValue type cast
+
 #### 2.9.0-alpha.1
   - fix typo: rename `methodisSpeakerphoneEnabled` to `isSpeakerphoneEnabled`
   - events deprecated & instead:

ios/RCTAgora/RCTAgora.m

     }
   }
   if (options[@"secret"] != nil) {
-    [self.rtcEngine setEncryptionSecret:[options[@"secret"] stringValue]];
+    [self.rtcEngine setEncryptionSecret:[options[@"secret"]]];
     if (options[@"secretMode"] != nil) {
-      [self.rtcEngine setEncryptionMode:[options[@"secretMode"] stringValue]];
+      [self.rtcEngine setEncryptionMode:[options[@"secretMode"]]];
     }
   }
   
   config.audioBitrate = [options[@"config"][@"audioBitrate"] integerValue];
   config.audioChannels = [options[@"config"][@"audioChannels"] integerValue];
   
-  NSInteger res = [self.rtcEngine addInjectStreamUrl:[options[@"url"] stringValue]
+  NSInteger res = [self.rtcEngine addInjectStreamUrl:[options[@"url"]]
                                               config:config];
   if (res == 0) {
     resolve(nil);
     transcoding.transcodingUsers = transcodingUsers;
   }
   if ([options objectForKey:@"transcodingExtraInfo"]) {
-    transcoding.transcodingExtraInfo = [options[@"transcodingExtraInfo"] stringValue];
+    transcoding.transcodingExtraInfo = [options[@"transcodingExtraInfo"]];
   }
   
   NSInteger res = [self.rtcEngine setLiveTranscoding:transcoding];