Raise the min julia version to 1.3

[oxinabox]

As discussed in #354 raising min version to 1.3 will let use InlineStrings.jl

[oxinabox]

1.3 tests are failing as in julia 1.3 JULIA_NUMTHREADS enviroment variable was only way to set number of threads.
But tests use julia -t instead.
I will fix on monday

[omus]

I'd be okay with setting the minimum to 1.3.2 to clear out this:

TimeZones.jl/src/compat.jl

Lines 13 to 44 in 0e67ab1

	if v"1.3.1-pre.18" <= VERSION < v"1.3.2"
	using Pkg.Artifacts: do_artifact_str, find_artifacts_toml, load_artifacts_toml
	# A copy of `Pkg.Artifacts.@artifact_str` where `name` is properly escaped on
	# Julia 1.3.1
	# https://github.com/JuliaLang/Pkg.jl/issues/1912
	# https://github.com/JuliaLang/Pkg.jl/pull/1580
	macro artifact_str(name)
	# Load Artifacts.toml at compile time, so that we don't have to use `__source__.file`
	# at runtime, which gets stale if the `.ji` file is relocated.
	local artifacts_toml = find_artifacts_toml(string(__source__.file))
	if artifacts_toml === nothing
	error(string(
	"Cannot locate '(Julia)Artifacts.toml' file when attempting to use artifact '",
	name,
	"' in '",
	__module__,
	"'",
	))
	end
	local artifact_dict = load_artifacts_toml(artifacts_toml)
	return quote
	# Invalidate .ji file if Artifacts.toml file changes
	Base.include_dependency($(artifacts_toml))
	# Use invokelatest() to introduce a compiler barrier, preventing many backedges from being added
	# and slowing down not only compile time, but also `.ji` load time. This is critical here, as
	# artifact"" is used in other modules, so we don't want to be spreading backedges around everywhere.
	Base.invokelatest(do_artifact_str, $(esc(name)), $(artifact_dict), $(artifacts_toml), $__module__)
	end
	end

[oxinabox]

I'd be okay with setting the minimum to 1.3.2 to clear out this:

Turns out there is no 1.3.2.
The last 1.3 release was 1.3.1, so that code is needed to support 1.3 at all.

[codecov-commenter]

Codecov Report

Merging #361 (fcf6e78) into master (22a32d4) will increase coverage by 0.97%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master     #361      +/-   ##
==========================================
+ Coverage   93.30%   94.27%   +0.97%     
==========================================
  Files          32       32              
  Lines        1613     1607       -6     
==========================================
+ Hits         1505     1515      +10     
+ Misses        108       92      -16     

Impacted Files	Coverage Δ
src/types/timezone.jl	94.28% <ø> (+2.61%)	⬆️
src/tzdata/download.jl	96.15% <ø> (-0.08%)	⬇️
src/tzdata/build.jl	68.75% <46.66%> (+5.70%)	⬆️
src/winzone/WindowsTimeZoneIDs.jl	100.00% <100.00%> (+40.90%)	⬆️
src/tzdata/version.jl	81.57% <0.00%> (-10.53%)	⬇️
src/tzdata/archive.jl	100.00% <0.00%> (ø)
src/local.jl	88.88% <0.00%> (+0.13%)	⬆️
src/build.jl	100.00% <0.00%> (+16.66%)	⬆️
... and 1 more

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[omus]

A couple more changes needed:

TimeZones.jl/src/tzdata/download.jl

Lines 4 to 9 in 0e67ab1

	if VERSION >= v"1.6.0-DEV.923"
	# Use Downloads.jl once TimeZones.jl drops support for Julia versions < 1.3
	download(args...) = Base.invokelatest(Base.Downloads().download, args...)
	else
	using Base: download
	end

TimeZones.jl/src/winzone/WindowsTimeZoneIDs.jl

Lines 56 to 61 in 0e67ab1

	@static if VERSION >= v"1.3"
	artifact_dir = @artifact_str "unicode-cldr-$UNICODE_CLDR_VERSION"
	cp(joinpath(artifact_dir, WINDOWS_ZONE_FILE), xml_file, force=true)
	else
	download(WINDOWS_ZONE_URL, xml_file)
	end

[omus]

Overall looks good. I've identified a few more things we can clear out due to dropping Julia 1.0 (e.g. tzdata_download and friends) but I can tackle that in another PR.

[omus]

I just notice this is backwards. Will address

[oxinabox]

oops my bad.