Update LanguageServer in the background

[Pangoraw]

Updating the language server is not currently supported:

zed-julia/src/julia.rs

Lines 29 to 40 in adc31ce

	// TODO: handle LanguageServer.jl updates.
	r#"
	import Pkg, UUIDs
	ls_uuid = UUIDs.UUID("2b0e0bc5-e4fd-59b4-8912-456d1b03d8d7")
	if !haskey(Pkg.dependencies(), ls_uuid)
	Pkg.add(Pkg.PackageSpec(uuid=ls_uuid))
	end
	using LanguageServer
	runserver()
	"#

Users can of course update it themselves using @zed-julia global environment but I think it would be nice to launch a task in the background to try to update LS.jl.