Interrupting the `edit` command leaves a temporary file in the config directory

[rossmacarthur]

To reproduce

EDITOR="code --wait" sheldon edit

Press Ctrl-C while VS Code is open.

$ ls ~/.sheldon
plugins-tmp-5232.toml
plugins.lock
plugins.toml
repos

[rossmacarthur]

I think we should probably just use the same temporary file and if the user tries to edit again we tell the user and ask if they want to reopen or delete it.

[rossmacarthur]

Fixed in 24437c3