Revert "chore: update pubspec.lock"

This reverts commit 1eebe45b492dcf2fcab4dfc18fe9207a5aa65177.

Travis fails: https://travis-ci.org/angular/angular.dart/builds/31741920
chore(style): cleanup to match g3v1x
chore(view_factory): register cache as ViewCache
fix(web_platform): include selector in viewFactoryCache key
chore(introspection): delete introspection_js.dart

This was incorrectly resurrected.