prep for publishing 0.12.12 (#188)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9b1d426..2511a04 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,7 @@
-## 0.12.12-dev
+## 0.12.12
+
+* Add a best practices section to readme.
+* Populate the pubspec `repository` field.
 
 ## 0.12.11
 
diff --git a/README.md b/README.md
index 56a2026..9244b2a 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,7 @@
+[![Dart CI](https://github.com/dart-lang/matcher/actions/workflows/ci.yml/badge.svg)](https://github.com/dart-lang/matcher/actions/workflows/ci.yml)
+[![pub package](https://img.shields.io/pub/v/matcher.svg)](https://pub.dev/packages/matcher)
+[![package publisher](https://img.shields.io/pub/publisher/matcher.svg)](https://pub.dev/packages/matcher/publisher)
+
 Support for specifying test expectations, such as for unit tests.
 
 The matcher library provides a third-generation assertion mechanism, drawing
diff --git a/pubspec.yaml b/pubspec.yaml
index aea5667..a5dfc22 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: matcher
-version: 0.12.12-dev
+version: 0.12.12
 description: >-
   Support for specifying test expectations via an extensible Matcher class.
   Also includes a number of built-in Matcher implementations for common cases.