readme: add bb compatible badge

Lets folks know, at-a-glance that this library will work with babashka!

Author: lread

README.md

@@ -1,7 +1,7 @@
 # lambdaisland/deep-diff2
 
 <!-- badges -->
-[![CircleCI](https://circleci.com/gh/lambdaisland/deep-diff2.svg?style=svg)](https://circleci.com/gh/lambdaisland/deep-diff2) [![cljdoc badge](https://cljdoc.org/badge/lambdaisland/deep-diff2)](https://cljdoc.org/d/lambdaisland/deep-diff2) [![Clojars Project](https://img.shields.io/clojars/v/lambdaisland/deep-diff2.svg)](https://clojars.org/lambdaisland/deep-diff2)
+[![CircleCI](https://circleci.com/gh/lambdaisland/deep-diff2.svg?style=svg)](https://circleci.com/gh/lambdaisland/deep-diff2) [![cljdoc badge](https://cljdoc.org/badge/lambdaisland/deep-diff2)](https://cljdoc.org/d/lambdaisland/deep-diff2) [![Clojars Project](https://img.shields.io/clojars/v/lambdaisland/deep-diff2.svg)](https://clojars.org/lambdaisland/deep-diff2) [![bb compatible](https://raw.githubusercontent.com/babashka/babashka/master/logo/badge.svg)](https://babashka.org)
 <!-- /badges -->
 
 Recursively compare Clojure or ClojureScript data structures, and produce a colorized diff of the result.