[skip ci] fix slack badge

Author: frenchy64

README.md

@@ -3,7 +3,7 @@
 [![Build Status](https://github.com/metosin/compojure-api/actions/workflows/build.yml/badge.svg)](https://github.com/metosin/compojure-api/actions)
 [![cljdoc badge](https://cljdoc.org/badge/metosin/compojure-api)](https://cljdoc.org/d/metosin/compojure-api/)
 [![Clojars Project](https://img.shields.io/clojars/v/metosin/compojure-api.svg)](https://clojars.org/metosin/compojure-api)
-[![Slack](https://img.shields.io/badge/clojurians-ring-swagger-blue.svg?logo=slack)](https://clojurians.slack.com/messages/ring-swagger/)
+[![Slack](https://img.shields.io/badge/clojurians-ring_swagger-blue.svg?logo=slack)](https://clojurians.slack.com/messages/ring-swagger/)
 
 Stuff on top of [Compojure](https://github.com/weavejester/compojure) for making sweet web apis.