Update / replace Libz registration for .gz files

[kescobo]

See https://github.com/BioJulia/Libz.jl/issues/68

Libz.jl is no longer maintained, and now recommends folks use CodecZlib instead. In any case, the implementation for Libz.jl is no longer functional.

julia> FileIO.load("test.log.gz")
Error encountered while load File{DataFormat{:GZIP}, String}("test.log.gz").

Fatal error:
ERROR: UndefVarError: load not defined

[timholy]

Did it ever work? Libz doesn't even load FileIO.

I'm happy to make the change, but first I want to just check that there's nothing broken here.

[kescobo]

Oh, no idea :laughing:

The FileIO docs point to Libz as being used for .gz files. I would not be surprised if that connection is not maintained if there were changes to the FileIO interface at somepoint in the last 2 years.

[CiaranOMara]

CodecZlib.jl doesn't appear to implement the FileIO loaders or savers either.