fix(nix): Support retrieving differently cased top-level attributes

As described in issue #14, the registry API does not allow image names
with uppercase-characters in them.

However, the Nix package set has several top-level keys with uppercase
characters in them which could previously not be retrieved using
Nixery.

This change implements a method for retrieving those keys, but it is
explicitly only working for the top-level package set as nested
sets (such as `haskellPackages`) often contain packages that differ in
case only.

0 files changed, 0 insertions, 0 deletions