fix(deps): update dependency rxdart_ext to v0.3.0

Author: renovate[bot]

pubspec.yaml

@@ -11,7 +11,7 @@ environment:
 
 dependencies:
   disposebag: ^1.5.1
-  rxdart_ext: ^0.2.5
+  rxdart_ext: 0.3.0
   flutter:
     sdk: flutter
   meta: ^1.7.0