build(dependencies): add collection package

- Add collection dependency version 1.19.1 to pubspec.yaml

Author: fulleni

pubspec.yaml

@@ -7,6 +7,7 @@ environment:
   sdk: ^3.9.0
 
 dependencies:
+  collection: ^1.19.1
   core:
     git:
       url: https://github.com/flutter-news-app-full-source-code/core.git