Add Zulip to GitLab's applications page
This commit adds Zulip https://zulipchat.com/ to GitLab's page for its Application Partners.
Edited by username-removed-1129123
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
This commit adds Zulip https://zulipchat.com/ to GitLab's page for its Application Partners.