Update Gem Version image.

Author: gkellogg

README.md

@@ -3,7 +3,7 @@ An implementation of the JSON Canonicalization Scheme for Ruby
 
 Implements [RFC8785](https://datatracker.ietf.org/doc/html/rfc8785) (JSON Canonicalization Scheme) in Ruby.
 
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+[![Gem Version](https://badge.fury.io/rb/json-canonicalization.svg)](http://badge.fury.io/rb/json-canonicalization)
 [![Build Status](https://github.com/dryruby/json-canonicalization/workflows/CI/badge.svg?branch=develop)](https://github.com/dryruby/json-canonicalization/actions?query=workflow%3ACI)
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