Bump Pkg version to include fix to git tree hash calculation

[staticfloat]

This fixes some recently-reported issues with restrictive umask's and
the Pkg.Artifacts git tree hash calculation.

X-ref: JuliaPackaging/BinaryBuilder.jl#527

[StefanKarpinski]

This fix alone would be a candidate for a very quick 1.3.1 release since the umask artifact issue is rather bad.

[giordano]

Does this include improvement of loading time of jll packages? Also that would be good to have in 1.3.1

[staticfloat]

This fix alone would be a candidate for a very quick 1.3.1 release since the umask artifact issue is rather bad.

Note that this is to update master; to update release-1.3 we should use a separate PR that bases itself off of @fredrikekre's very helpful 1.3 backports branch.

Does this include improvement of loading time of jll packages? Also that would be good to have in 1.3.1

Yes, both this PR and Fredrik's 1.3 backporting branch contain the speedups.

[KristofferC]

For precompilation time of jll packages we also need to use some of the artifact functionality in the precompile script. I agree we should get a 1.3.1 out fairly quickly.

[KristofferC]

Should include JuliaLang/Pkg.jl#1517 here as well, since right now, master is pretty broken for packages overall.

[staticfloat]

For precompilation time of jll packages we also need to use some of the artifact functionality in the precompile script.

We could do something like download a JLL package into the Julia source directory (before the build) and install the artifacts somewhere, then using it within the precompile script to precompile the loading code (but not the downloading code). Is that what you have in mind?

[KristofferC]

We could do something like download a JLL package into the Julia source directory (before the build) and install the artifacts somewhere, then using it within the precompile script to precompile the loading code (but not the downloading code). Is that what you have in mind?

Yeah, just bundle something with Pkg that allows us to use the artifact macro in the precompile script.

[staticfloat]

JuliaLang/Pkg.jl#1521