Use quiver directly, and update README.google.  This is so that
we don't have to fork quiver_hashcode as well.

BUG=
R=whesse@google.com

Review-Url: https://codereview.chromium.org/2944463002 .
diff --git a/README.google b/README.google
index 89f8df3..d9ad278 100644
--- a/README.google
+++ b/README.google
@@ -9,4 +9,5 @@
 This directory contains the tuple package as checked
 out from git@github.com:kseo/tuple.git at tag v1.0.1
 on June 13, 2017.
-
+Modified to use quiver.core directly instead of
+quiver_hashcode.
diff --git a/lib/tuple.dart b/lib/tuple.dart
index 149fd7c..115d8af 100644
--- a/lib/tuple.dart
+++ b/lib/tuple.dart
@@ -22,6 +22,6 @@
 /// ```
 library tuple;
 
-import 'package:quiver_hashcode/hashcode.dart';
+import 'package:quiver/core.dart';
 
 part 'package:tuple/src/tuple.dart';
diff --git a/pubspec.yaml b/pubspec.yaml
index 48bc8c3..d60177c 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -8,6 +8,6 @@
 environment:
   sdk: '>=1.6.0'
 dependencies:
-  quiver_hashcode: '>=1.0.0-dev.1 <1.1.0'
+  quiver: '>=0.22.0 <0.23.0'
 dev_dependencies:
   test: any