Add version option to LaTeX format

[mortenpi]

@inkydragon This is what I had in mind as a stopgap solution for the version, until we support it for all formats in makedocs. Do the changes look good to you?

[inkydragon]

Looks good. Build locally works well.

---

And ...

Documenter.jl/src/Writers/LaTeXWriter.jl

Lines 107 to 112 in 401718b

	let tag = get(ENV, "TRAVIS_TAG", "")
	if occursin(Base.VERSION_REGEX, tag)
	v = VersionNumber(tag)
	name *= "-$(v.major).$(v.minor).$(v.patch)"
	end
	end

            if occursin(Base.VERSION_REGEX, settings.version)
                v = VersionNumber(settings.version)
                name *= "-$(v.major).$(v.minor).$(v.patch)"
            end

[mortenpi]

Good catch @inkydragon!