use VersionParsing.jl to parse version numbers

[stevengj]

I notice that you have some custom code for parsing foreign version numbers via VersionNumber(string). You might try vparse from https://github.com/stevengj/VersionParsing.jl instead.

julia> vparse("0.12.head")
v"0.12.0+head"

[malmaud]

Thanks, this looks great!