use lsp-mode gitter badge

Author: brotzeit

README.md

@@ -2,7 +2,7 @@ lsp-ui
 ======
 
 [![MELPA](https://melpa.org/packages/lsp-ui-badge.svg)](https://melpa.org/#/lsp-ui)
-[![Join the chat](https://badges.gitter.im/emacs-lsp/lsp-ui.svg)](https://gitter.im/emacs-lsp/lsp-ui)
+[![](https://badges.gitter.im/emacs-lsp/lsp-mode.svg)](https://gitter.im/emacs-lsp/lsp-mode)
 [![Build Status](https://github.com/emacs-lsp/lsp-ui/workflows/CI/badge.svg?branch=master)](https://github.com/emacs-lsp/lsp-ui/actions)
 
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