Problem: we cannot handle versioned dependencies

[clacke]

Example:

              (dependencies
               .
               ("base"
                "draw-lib"
                "drracket"
                ("gui-lib" #:version "1.16")

Currently we won't even be able to do an incorrect parsing of this, I'm guessing we'll get a type error for expecting a string when there's a pair.

Solution: Maybe short-term we could try getting away with just ignoring the version, just like we are ignoring the platform of platform-dependent packages in the release catalog.

Long-term we'll have to rework things to allow for our nix expression to address several versions of the same package.