Aspnetcore: Update Omnisharp to Roslyn 3.7

[ryanbrandenburg]

We can't update to Roslyn 3.7 until Omnisharp does because types passed between our projects need to be recognized as of the same type.

@JoeRobich is there an ETA on OmniSharp taking 3.7?

CC @NTaylorMullen

[JoeRobich]

@ryanbrandenburg I'll look into getting it updated to a recent build tomorrow morning.

[NTaylorMullen]

fyi @captainsafia

[captainsafia]

Thanks @JoeRobich! Let us know how this goes today.

[captainsafia]

Synced with @JoeRobich out-of-GitHub. It looks like the Roslyn update will happen so we do not need to worry about reverting on our end.

[JoeRobich]

@captainsafia I updated OmniSharp to Roslyn 3.7. Will do a new release of OmniSharp once this goes in https://github.com/OmniSharp/omnisharp-roslyn/pull/1805. Then I can update the C# extension.

[JoeRobich]

New release of OmniSharp is live with Roslyn 3.7.0. https://github.com/OmniSharp/omnisharp-vscode/pull/3799 is the PR to update in the C# extension.

[JoeRobich]

And we now have a new C# prerelease using the new OmniSharp. Once the razor tooling it updated, we can get a build out to vendors for prerelease testing.