Release version 0.12.13+5.

This version hasn't been released yet.

R=jakemac@google.com, kevmoo@google.com

Review URL: https://codereview.chromium.org//2048773002 .
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f280ae4..5637fa5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,9 +1,7 @@
-## 0.12.13+6
+## 0.12.13+5
 
 * Declare support for version 1.18 of the Dart SDK.
 
-## 0.12.13+5
-
 * Use the latest `collection` package.
 
 ## 0.12.13+4
diff --git a/pubspec.yaml b/pubspec.yaml
index 5679b54..a8af982 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: test
-version: 0.12.13+6
+version: 0.12.13+5
 author: Dart Team <misc@dartlang.org>
 description: A library for writing dart unit tests.
 homepage: https://github.com/dart-lang/test