Update pubspec for version solving in Dart 2 stable

PiperOrigin-RevId: 207339085

Author: nshahan

pubspec.yaml

@@ -1,15 +1,15 @@
 name: angular_components
-version: 0.9.0-beta+2
+version: 0.9.0-beta+3
 description: >
   The official Material Design components for AngularDart. Used at Google
   in production apps.
 homepage: https://webdev.dartlang.org/components
 author: Dart Team <[email protected]>
 environment:
-  sdk: '>=2.0.0-dev.64.2 <3.0.0'
+  sdk: '>=2.0.0-dev.68.0 <3.0.0'
 dependencies:
-  angular: ^5.0.0-beta+2
-  angular_forms: ^2.0.0-beta+2
+  angular: ^5.0.0-beta+3
+  angular_forms: ^2.0.0-beta+3
   async: ^2.0.6
   build: '>=0.11.1 <0.13.0'
   build_config: '>=0.2.6 <0.4.0'
@@ -21,7 +21,6 @@ dependencies:
   logging: ^0.11.2
   meta: ^1.0.4
   observable: ^0.22.1+3
-  protobuf: ^0.8.0
-  perf_api: ^0.1.0
+  protobuf: ^0.9.0
   quiver: '>=0.24.0 <0.30.0'
   sass_builder: ^2.0.2