test: update to latest pkg:test (#53)

Also remove unused import
diff --git a/lib/src/hash_sink.dart b/lib/src/hash_sink.dart
index fde6b08..0a61e36 100644
--- a/lib/src/hash_sink.dart
+++ b/lib/src/hash_sink.dart
@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:typed_data';
-import 'dart:math' as math;
 
 import 'package:typed_data/typed_data.dart';
 
diff --git a/pubspec.yaml b/pubspec.yaml
index ff8f0aa..0b974b0 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -10,4 +10,4 @@
   convert: '>=1.0.0 <3.0.0'
   typed_data: '^1.0.0'
 dev_dependencies:
-  test: '^0.12.17'
+  test: ^1.0.0