Update README.md

Author: paulofaria

README.md

@@ -2,7 +2,6 @@
 
 [![Swift][swift-badge]][swift-url]
 [![License][mit-badge]][mit-url]
-[![Slack][slack-badge]][slack-url]
 [![GitHub Actions][gh-actions-badge]][gh-actions-url]
 [![Codebeat][codebeat-badge]][codebeat-url]
 
@@ -159,9 +158,6 @@ This project is released under the MIT license. See [LICENSE](LICENSE) for detai
 [mit-badge]: https://img.shields.io/badge/License-MIT-blue.svg?style=flat
 [mit-url]: https://tldrlegal.com/license/mit-license
 
-[slack-badge]: http://slack.zewo.io/badge.svg
-[slack-url]: http://slack.zewo.io
-
 [gh-actions-badge]: https://github.com/GraphQLSwift/GraphQL/workflows/Build/badge.svg
 [gh-actions-url]: https://github.com/GraphQLSwift/GraphQl/actions?query=workflow%3ABuild