Update web-angular to latest

CHANGELOG.md

+## 1.0.13
+
+- Updated `web-angular` to `2.0.0-beta.21`
+
 ## 1.0.12
 
 - Add commented-out `.analysis_options` file to all templates.

pubspec.yaml

@@ -4,7 +4,7 @@
 
 name: stagehand
 # When changing this version, change the lib/src/cli_app.dart version as well.
-version: 1.0.12
+version: 1.0.13
 description: >
   A scaffolding generator for your Dart projects. Stagehand helps you get set
   up!

templates/web-angular/pubspec.yaml

@@ -2,16 +2,12 @@ name: __projectName__
 description: A Dart app that uses Angular 2
 version: 0.0.1
 environment:
-  sdk: '>=1.13.0 <2.0.0'
+  sdk: '>=1.19.0 <2.0.0'
 dependencies:
-  angular2: 2.0.0-beta.20
+  angular2: 2.0.0-beta.21
   browser: ^0.10.0
   dart_to_js_script_rewriter: ^1.0.1
 transformers:
 - angular2:
-    platform_directives:
-    - 'package:angular2/common.dart#COMMON_DIRECTIVES'
-    platform_pipes:
-    - 'package:angular2/common.dart#COMMON_PIPES'
     entry_points: web/main.dart
 - dart_to_js_script_rewriter