Add release status badge to README (#4102)

README.md

diff --git a/README.md b/README.md
index 1dd6d80..2d8f4f5 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,7 @@
 # Flutter plugins
 
 [![Build Status](https://api.cirrus-ci.com/github/flutter/plugins.svg)](https://cirrus-ci.com/github/flutter/plugins/master)
+[![Release Status](https://github.com/flutter/plugins/actions/workflows/release.yml/badge.svg)](https://github.com/flutter/plugins/actions/workflows/release.yml)
 
 This repo is a companion repo to the main [flutter
 repo](https://github.com/flutter/flutter). It contains the source code for