Use BASE64 from package:convert.

Closes #4

R=kevmoo@google.com

Review URL: https://codereview.chromium.org//1834343003 .
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a74290e..b9e1db0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.0.2
+
+* Properly use `BASE64` from `dart:convert` rather than `crypto`.
+
 ## 1.0.1
 
 * Add support for `crypto` 1.0.0.
diff --git a/lib/src/channel.dart b/lib/src/channel.dart
index 3d1d492..9c82c68 100644
--- a/lib/src/channel.dart
+++ b/lib/src/channel.dart
@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:convert' as convert;
 
 import 'package:async/async.dart';
 import 'package:crypto/crypto.dart';
@@ -64,7 +65,8 @@
   static String signKey(String key) {
     // We use [codeUnits] here rather than UTF-8-decoding the string because
     // [key] is expected to be base64 encoded, and so will be pure ASCII.
-    return BASE64.encode(sha1.convert((key + webSocketGUID).codeUnits).bytes);
+    return convert.BASE64.encode(
+        sha1.convert((key + webSocketGUID).codeUnits).bytes);
   }
 
   /// Creates a new WebSocket handling messaging across an existing [channel].
diff --git a/pubspec.yaml b/pubspec.yaml
index a4853c9..b7bd90e 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,11 +1,11 @@
 name: web_socket_channel
-version: 1.0.1
+version: 1.0.2
 description: StreamChannel wrappers for WebSockets.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/dart-lang/web_socket_channel
 
 environment:
-  sdk: '>=1.8.0 <2.0.0'
+  sdk: '>=1.13.0 <2.0.0'
 
 dependencies:
   async: '^1.3.0'