Update readme with walkthrough video demonstrating opening a PR on this repo

[ruf-io]

Create a screenshare video with either captions or voiceover that walks a user through the steps required to make a basic "New Term" Pull Request on this repo.

Upload the screenshare video to youtube, upload an image screenshot to an image hosting service or CDN and add the image , linked to the YouTube video, in the readme.

[lynmuldrow]

I can take this on! I have the assets and flow down to create a walkthrough video that helps folks contribute. Thanks for considering.

[lynmuldrow]

I did a livestream walkthrough that can be previewed here: https://www.twitch.tv/videos/765484415

I'm happy to create another, shorter video, without Christmas music and with more of a focus on fork > clone > create > add > commit > push > PR.