Bump version of .NET Standard to 2.1

[terrajobst]

This should include:

• TFM version
• Assembly version
• File informational version
• File version
• Package version

[terrajobst]

@ericstj, are you the right person to work on this, now that @weshaggard has switched teams?

[ericstj]

Maybe? /cc @danmosemsft @AlexGhiondea in case they have an opinion.

[terrajobst]

Looks like @wtgodbe is the happy winner 😄

[wtgodbe]

The package is already versioned at 2.1, but the binary itself still needs its version updated

[wtgodbe]

Currently the ref assembly for netstandard.dll is versioned at 1.1, while the shims are 4.7. This changed here: 501d547#diff-82d0524075c8f50a0573bb8342f78146. Previously these binaries were versioned 1.0 & 4.6 respectively. My understanding here is that we'd want to continue to version these linearly, rather than forcing either or both to 2.1, and that we're OK with just maintaining the package version at 2.1 (then upgrading linearly from there). @weshaggard @ericstj does that sound right?

[ericstj]

Can you clarify what version you are talking about? File Version or Assembly Version?

If I look at 2.0.x I see the following:

file	file version	assembly version
nestandard.dll	1.0.nnnn.mm	2.0.0.0
desktop shims	4.6.nnnn.mm	4.0.0.0
netstandard1.x shims	4.6.nnnn.mm	last assembly version of contract that is subsumed

For file-versions you just need to make sure you keep monotonically increasing them. For assembly versions of shims they should remain unchanged since you aren't subsuming any newer versions of those assemblies. For assembly version of netstandard.dll it should increase to 2.1.0.0.

[wtgodbe]

I was looking at FileVersion. All of those have bumped the MinorVersion by 1 since 2.0, but it looks like the AssemblyVersion for netstandard.dll is still 2.0.0.0. I'll fix that to be 2.1.0.0.