Remove references to CodeClimate (#31)

Author: jgarber623

.github/workflows/ci.yml

@@ -44,4 +44,3 @@ jobs:
           bundler-cache: true
           ruby-version: ${{ matrix.ruby }}
       - run: bundle exec rspec
-      - uses: paambaati/codeclimate-action@v5.0.0

README.md

@@ -5,8 +5,6 @@
 [![Gem](https://img.shields.io/gem/v/webmention.svg?logo=rubygems&style=for-the-badge)](https://rubygems.org/gems/webmention)
 [![Downloads](https://img.shields.io/gem/dt/webmention.svg?logo=rubygems&style=for-the-badge)](https://rubygems.org/gems/webmention)
 [![Build](https://img.shields.io/github/actions/workflow/status/indieweb/webmention-client-ruby/ci.yml?branch=main&logo=github&style=for-the-badge)](https://github.com/indieweb/webmention-client-ruby/actions/workflows/ci.yml)
-[![Maintainability](https://img.shields.io/codeclimate/maintainability/indieweb/webmention-client-ruby.svg?logo=code-climate&style=for-the-badge)](https://codeclimate.com/github/indieweb/webmention-client-ruby)
-[![Coverage](https://img.shields.io/codeclimate/c/indieweb/webmention-client-ruby.svg?logo=code-climate&style=for-the-badge)](https://codeclimate.com/github/indieweb/webmention-client-ruby/code)
 
 ## Key Features