Bumped upper webview_flutter version limit to 4.0.0 not included

Author: NirmalAriyathilake

pubspec.yaml

@@ -22,7 +22,7 @@ dependencies:
   chewie: '>=1.1.0 <2.0.0'
 
   # Plugin for rendering the <iframe> tag.
-  webview_flutter: '>=2.0.4 <=3.0.0'
+  webview_flutter: '>=2.0.4 <4.0.0'
 
   # Plugins for rendering the <audio> tag.
   chewie_audio: '>=1.2.0 <2.0.0'