add tableflip spinner

[leifwalsh]

Description of new feature, or changes

Adds a spinner that looks like two characters flipping a table back and forth

Checklist

• [x] Your branch is up-to-date with the base branch
• [ ] You've included at least one test if this is a new feature
• [x] All tests are passing

Related Issues and Discussions

People to notify

[leifwalsh]

@manrajgrover need anything from me?

[manrajgrover]

@leifwalsh Thanks for working on this. Since this spinner is user contributed, I was thinking of creating a separate dictionary for user contributed spinners and combine them with cli-spinners before creating Enum. Can you make these changes and I can then review the code?

[leifwalsh]

It's not clear what you're asking for here