adding sliver tools

pubspec.yaml

@@ -3,7 +3,7 @@ description: A new Flutter project.
 
 # The following line prevents the package from being accidentally published to
 # pub.dev using `flutter pub publish`. This is preferred for private packages.
-publish_to: 'none' # Remove this line if you wish to publish to pub.dev
+publish_to: "none" # Remove this line if you wish to publish to pub.dev
 
 # The following defines the version and build number for your application.
 # A version number is three numbers separated by dots, like 1.2.43
@@ -37,6 +37,7 @@ dependencies:
   scrollable_positioned_list: ^0.3.4
   shared_preferences: ^2.0.15
   shimmer: ^2.0.0
+  sliver_tools: ^0.2.8
   url_launcher: ^6.1.5
   url_strategy: ^0.2.0
   uuid: ^3.0.6