Add WinGet installation instructions

[phrkdll]

I recognized that there seems to be a WinGet manifest pointing at the cantino/mcfly repository. So I thought it would be nice having installation instructions for that in the README.

[cantino]

Thanks! Do you know how the WinGet manifest is maintained? It's not something I was aware of.

[phrkdll]

Thanks! Do you know how the WinGet manifest is maintained? It's not something I was aware of.

No, sorry. I only saw that it's available via WinGet and dug a little to verify that it's really coming from here.

What I found on publishing to WinGet is this:
https://learn.microsoft.com/en-us/windows/package-manager/package/

And this is where the manifests finally end up:
https://github.com/microsoft/winget-pkgs/tree/master/manifests/a/AndrewCantino/McFly

There's also a GitHub action availabe:
https://github.com/marketplace/actions/winget-publish

But that's all I know so far.

mcfly is a great tool, by the way! Can't live without it anymore!