Update upper SDK constraint to 3.0.0 (#7)

* Update upper SDK constraint to 3.0.0

* Update CHANGELOG.md

* Updated version to 0.1.3
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6434e87..3271b83 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## v0.1.3
+
+* Updated SDK version upper bound to 3.0.0.
+
 ## v0.1.2
 
 * Require Dart 2.
diff --git a/pubspec.yaml b/pubspec.yaml
index c7d5a77..ae00db0 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,11 +1,11 @@
 name: sync_http
-version: 0.1.2
+version: 0.1.3
 author: Dart Team <misc@dartlang.org>
 description: Synchronous HTTP client for Dart.
 homepage: https://github.com/dart-lang/sync_http
 
 environment:
-  sdk: '>=2.0.0-dev.63 <2.0.0'
+  sdk: '>=2.0.0-dev.63 <3.0.0'
 
 dev_dependencies:
   test: ^1.2.0