Roll watcher dependency for web_ui to 1.1.0. (#42248)

Incoming dart sdk roll
https://dart.googlesource.com/sdk.git/+log/90b4df96e9dc..4881eadbade6
needs updated version of watcher due to FileSystemEvent becoming sealed.

Author: aam

lib/web_ui/pubspec.yaml

@@ -43,7 +43,7 @@ dev_dependencies:
   test_core: any
   typed_data: any
   uuid: 3.0.6
-  watcher: 1.0.0
+  watcher: 1.1.0
   web_socket_channel: any
   webdriver: 3.0.1
   webkit_inspection_protocol: any