Mark as compatible with shelf 0.6.0.

pubspec.yaml

Index: pubspec.yaml
diff --git a/pubspec.yaml b/pubspec.yaml
index a92453e55fad9b36aa60b06bccffe5d71c2d6ea5..0e3ddfb657e5c4e8e6ed2c4d71099696b2ff9a9b 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,12 +1,12 @@
 name: shelf_proxy
-version: 0.1.0+1
+version: 0.1.0+2
 author: Dart Team <misc@dartlang.org>
 description: A shelf handler for proxying requests to another server.
 homepage: https://github.com/dart-lang/shelf_proxy
 dependencies:
   http: '>=0.9.0 <0.12.0'
   path: '>=1.0.0 <2.0.0'
-  shelf: '>=0.5.2 <0.6.0'
+  shelf: '>=0.5.2 <0.7.0'
 dev_dependencies:
   browser: '>=0.10.0 <0.11.0'
   scheduled_test: '>=0.11.0 <0.12.0'