Docs: remove stale gitter badge from readme

Close gh-5273

README.md

@@ -1,7 +1,9 @@
 [jQuery](https://jquery.com/) — New Wave JavaScript
 ==================================================
 
-[![Gitter](https://badges.gitter.im/jquery/jquery.svg)](https://gitter.im/jquery/jquery?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
+Meetings are currently held on the [matrix.org platform](https://matrix.to/#/#jquery_meeting:gitter.im).
+
+Meeting minutes can be found at [meetings.jquery.org](https://meetings.jquery.org/category/core/).
 
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