Does not work with `lts/` prefix

[hbarcelos]

Running:

nodenv alias lts/fermium 14

yields the following error:

> lts/fermium => 14
> ln: failed to create symlink 'lts/fermium': File or directory does not exist

[airdrummingfool]

I was hoping to do this as well, specifically for better compatibility with .nvmrc files (which can list lts/* versions instead of just numbers).

Similarly, it doesn't look like I can alias to a specific name with --auto? I was hoping to do nodenv alias lts/fermium 14 --auto so that lts/fermium was always up-to-date with the latest v14 release.

Either way, thanks for this useful plugin!