Prepare to publish 0.9.0 (#368)

Author: natebosch

source_gen/pubspec.yaml

@@ -1,5 +1,5 @@
 name: source_gen
-version: 0.9.0-dev
+version: 0.9.0
 author: Dart Team <[email protected]>
 description: Automated source code generation for Dart.
 homepage: https://github.com/dart-lang/source_gen
@@ -10,6 +10,7 @@ dependencies:
   async: ^2.0.7
   build: ^0.12.4
   dart_style: '>=0.1.7 <2.0.0'
+  glob: ^1.1.0
   meta: ^1.1.0
   path: ^1.3.2
   source_span: ^1.4.0