docs: add deploy to Zeabur as another one-click solution

[MichaelYuhe]

Zeabur is a cloud hosting platform. I've created a template for users to deploy Hi.events with one click on Zeabur. Template: https://zeabur.com/templates/8DIRY6 Preview: https://tnbteb.zeabur.app/event/1/zeabur

Checklist

• [x] I have read the contributing guidelines.
• [x] My code is of good quality and follows the coding standards of the project.
• [x] I have tested my changes, and they work as expected.

[github-actions[bot]]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[MichaelYuhe]

I have read the CLA Document and I hereby sign the CLA

[daveearley]

Thanks @MichaelYuhe! And nice product!