Mark as deprecated

[frankier]

@rofinn This hasn't been updated in 4 years. Could you please mark it as deprecated? Issues like #62 are causing ecosystem slowdowns like MakieOrg/Makie.jl#4842 . Deprecating would make it easier to argue to switch away as with davidanthoff/Electron.jl#128

[davidanthoff]

I don't think this should be deprecated at this point. The package does what it is supposed to do, no need to make updates in that case?

I agree it would be time to move to package extensions to solve the problem, but that should come first before anything gets deprecated.

[rofinn]

Lol, one of these packages should probably still be marked as deprecated at some point. Assuming the package extensions work well and we're fine with dropping any pre-1.9 support :)