Remove link to Zulip archive.

Not kept up-to-date anymore.

pages/index.html

@@ -67,8 +67,7 @@
 <a href="https://github.com/coq-community/awesome-coq">Awesome Coq</a>
 curated list of projects and resources). We have a multi-lingual
 <a href="https://coq.discourse.group">Discourse forum</a> and a
-<a href="https://coq.zulipchat.com">Zulip chat</a> with a continuously updated
-<a href="https://coq.gitlab.io/zulip-archive/">openly accessible archive</a>.
+<a href="https://coq.zulipchat.com">Zulip chat</a>.
 </p>
 
 <p>Note our <a href="https://github.com/coq/coq/blob/master/CODE_OF_CONDUCT.md">code of conduct</a>