update yaml

Author: dujiepeng

pubspec.yaml

@@ -5,6 +5,7 @@ homepage: http://www.easemob.com/product/im
 
 environment:
   sdk: '>=2.12.0 <3.0.0'
+  flutter: ">=2.0.0"
 
 dependencies:
   flutter:
@@ -27,8 +28,13 @@ flutter:
 
 
   plugin:
-    androidPackage: com.easemob.im_flutter_sdk
-    pluginClass: ImFlutterSdkPlugin
+    platforms:
+      android:
+        package: com.easemob.im_flutter_sdk
+        pluginClass: ImFlutterSdkPlugin
+      ios:
+        pluginClass: ImFlutterSdkPlugin
+
 
 
   # To add assets to your plugin package, add an assets section, like this: