Replace Gitter with Zulip (#2254)

Author: sanketverma1704

.github/ISSUE_TEMPLATE/config.yml

@@ -3,9 +3,9 @@ contact_links:
   - name: ✨ Propose a new major feature
     url: https://github.com/zarr-developers/zarr-specs
     about: A new major feature should be discussed in the Zarr specifications repository.
-  - name: ❓ Discuss something on gitter
-    url: https://gitter.im/zarr-developers/community
-    about: For questions like "How do I do X with Zarr?", you can move to our Gitter channel.
+  - name: ❓ Discuss something on ZulipChat
+    url: https://ossci.zulipchat.com/
+    about: For questions like "How do I do X with Zarr?", you can move to our ZulipChat.
   - name: ❓ Discuss something on GitHub Discussions
     url: https://github.com/zarr-developers/zarr-python/discussions
     about: For questions like "How do I do X with Zarr?", you can move to GitHub Discussions.