xcodes should automatically update if it failed to find the provided version

[interstateone]

A common flow is:

1. Oh! A new Xcode 12.0.1 has been released
2. Open Terminal

$ xcodes install 12.0.1
Could not find version 12.0.1.

😔

$ xcodes update && xcodes install 12.0.1
(1/6) Downloading Xcode 12.0.1: 5%
...

---

Instead, it should work like:

1. Oh! A new Xcode 12.0.1 has been released
2. Open Terminal

$ xcodes install 12.0.1
Could not find version 12.0.1, but will update in case it's a recent release.
Updating...
(1/6) Downloading Xcode 12.0.1: 5%
...

---

It's still possible to fail, which would look like:

$ xcodes install 25.2
Could not find version 25.2, but will update in case it's a recent release.
Updating...
Could not find version 25.2.