docs: avoid orange color for gem badge

README.md

@@ -2,7 +2,7 @@
 
 Ruby implementation of RFC [8152](https://tools.ietf.org/html/rfc8152) CBOR Object Signing and Encryption (COSE)
 
-[![Gem](https://img.shields.io/gem/v/cose.svg?style=flat-square)](https://rubygems.org/gems/cose)
+[![Gem](https://img.shields.io/gem/v/cose.svg?style=flat-square&color=informational)](https://rubygems.org/gems/cose)
 [![Travis](https://img.shields.io/travis/cedarcode/cose-ruby.svg?style=flat-square)](https://travis-ci.org/cedarcode/cose-ruby)
 
 ## Installation