remove Gitter link from README

Signed-off-by: Justin Kaeser <justin.kaeser@jetbrains.com>

README.md

@@ -1,7 +1,6 @@
 [![official JetBrains project](http://jb.gg/badges/official.svg)](https://confluence.jetbrains.com/display/ALL/JetBrains+on+GitHub)
 [![Scala Plugin Build & Test](https://github.com/JetBrains/intellij-scala/actions/workflows/build.yml/badge.svg)](https://github.com/JetBrains/intellij-scala/actions/workflows/build.yml)
 [![Discord](https://badgen.net/badge/icon/discord?icon=discord&label)](https://discord.gg/aUKpZzeHCK)
-[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/JetBrains/intellij-scala)
 
 # Scala Plugin for IntelliJ IDEA