Video calling

[SuDa2103]

Collaborate Section Changed to Video Calling

[github-actions[bot]]

Visit the preview URL for this PR (updated for commit 09aae84):

https://gitlive-docs--pr50-video-calling-evag00i6.web.app

_{(expires Tue, 27 Apr 2021 13:32:37 GMT)}

_{🔥 via Firebase Hosting GitHub Action 🌎}