update dependencies

[ctaggart]

Bug reported by @shiftkey on twitter.
https://twitter.com/shiftkey/status/1222304183409369088

shiftkey/dotnetcore-sourcelink-test-bug#1

It think it may be fixed with just libraries update that I did to master earlier this week:
51e5b47#diff-13ab17208db6dc6f0e20af1ae8c0a6f7R12-R14

    <PackageReference Include="NuGet.Packaging" Version="4.4.0" />	    
    <PackageReference Include="NuGet.Packaging" Version="5.4.0" />
    <PackageReference Include="System.Reflection.Metadata" Version="1.5.0" />	    
    <PackageReference Include="System.Reflection.Metadata" Version="1.8.0" />

[shiftkey]

@ctaggart I can test my repro against master rather than a released package if you'd like to confirm that fixes it.

[ctaggart]

@shiftkey Sure test like this:

~/github/SourceLink/dotnet-sourcelink$ dotnet run --framework netcoreapp2.1 test ~/github/dotnetcore-sourcelink-test-bug/bin/Release/netstandard2.0/dotnetcore-sourcelink-test-bug.dll

[shiftkey]

Seems unchanged

$ git rev-parse HEAD
51e5b47ae64d87447a0803cec559947242fe935b
$ dotnet run --framework netcoreapp2.1 test ../../dotnetcore-sourcelink-test-bug/bin/Release/netstandard2.0/dotnetcore-sourcelink-test-bug.dll
1 Documents without URLs:
74a35b2e0310ee692c4338531afedfe18376f44d57ebf83466e7e6a5b80e2d14 sha256 csharp /var/folders/pp/1_6b120j6cs4w1bmhk9qgmy80000gn/T/.NETStandard,Version=v2.0.AssemblyAttributes.cs
1 Documents with errors:
16b05566980c715287c2d8427a4627e52b0979f43211a8d3d4ae7d90c9b54555 sha256 csharp /Users/shiftkey/src/dotnetcore-sourcelink-test-bug/obj/Release/netstandard2.0/dotnetcore-sourcelink-test-bug.AssemblyInfo.cs
https://raw.githubusercontent.com/shiftkey/dotnetcore-sourcelink-test-bug/e707de6428305d6a2bd997a516b5444592421cfd/obj/Release/netstandard2.0/dotnetcore-sourcelink-test-bug.AssemblyInfo.cs
error: url failed NotFound: Not Found
sourcelink test failed

[ctaggart]

😞 Probably need someone to finish #389. That is not something I will be contributing.

[shiftkey]

@ctaggart understandable, and thanks for all your hard work over the years with SourceLink.

If it turns out that #389 is the solution I'll see if I can revive it, but for now I need to understand more about the MSBuild changes that have introduced this problem to ensure I am fixing the right thing.