Add Zulip Terminal to Communication tools.

[amanagr]

Checklist for submitting a pull request to Terminals Are Sexy:

• [x] I have carefully read and comply with the Contributing Guidelines of this repo.
• [x] I have searched the PRs of this repo and believe that this is not a duplicate.

- **Title**: Zulip Terminal - **Link**: https://github.com/zulip/zulip-terminal - **Category**: Communication - **Description**: An interactive terminal interface for [Zulip](https://github.com/zulip)

[amanagr]

Hey, Great list of awesome terminal stuff. It would be great if you could give zulip terminal another try, it has changed a lot in the past few months and is being actively developed now. Thanks for your time...

[amanagr]

Hi, I am the maintainer of the zulip-terminal repository. What endorsement do you need?