Resolve rtools version by version and not just name

[cderv]

I stumbled upon this while doing

❯ rig system rtools rm 4.5
[INFO] Removing C:\rtools4.5
[ERROR] Cannot remove C:\rtools4.5: del : Impossible de trouver le chemin d'accès « C:\rtools4.5 », car il n'existe pas.
Au caractère Ligne:1 : 1
+ del -recurse -force C:\rtools4.5
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (C:\rtools4.5:String) [Remove-Item], ItemNotFoundException
    + FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.RemoveItemCommand

It took me time to understand I needed to use the name without dot

rig system rtools rm 45

Same for install doing

❯ rig system rtools add 4.5
[INFO] Rtools40 is already installed

because it requires

> rig system rtools add 45

It seems using 4.5 mapped to 4.0 which I have installed too

❯ rig system rtools list
name  version  full-version   path
------------------------------------------
40    4.0      4.0.3.0        C:\rtools40
43    4.3      4.3.5976.5975  C:\rtools43
44    4.4      4.4.6459.6401  C:\rtools44
45    4.5      4.5.6691.6492  C:\rtools45

Maybe a guided error message would be helpful, or resolving without the middle dot could help the user experience.