Update badges

Author: eed3si9n

README.md

@@ -1,6 +1,6 @@
-[![Build Status](https://travis-ci.com/sbt/sbt.svg?branch=develop)](https://travis-ci.com/github/sbt/sbt)
+[![CI](https://github.com/sbt/sbt/actions/workflows/ci.yml/badge.svg)](https://github.com/sbt/sbt/actions/workflows/ci.yml)
 [![Latest version](https://img.shields.io/github/tag/sbt/sbt.svg)](https://index.scala-lang.org/sbt/sbt)
-[![Gitter Chat](https://badges.gitter.im/sbt/sbt.svg)](https://gitter.im/sbt/sbt)
+[![Discord](https://img.shields.io/discord/632150470000902164?label=Discord%20%23sbt)](https://discord.com/channels/632150470000902164/922600050989875282)
 
   [sbt/sbt-zero-seven]: https://github.com/sbt/sbt-zero-seven
   [CONTRIBUTING]: CONTRIBUTING.md