Support for .Net 6.0.0

When running build.sh it fails with the following output:-

GNU bash, version 4.4.20(1)-release (x86_64-redhat-linux-gnu)
Microsoft (R) .NET Core SDK version 6.0.100
Microsoft (R) Build Engine version 17.0.0+c9eb9dd64 for .NET
Copyright (C) Microsoft Corporation. All rights reserved.

  Determining projects to restore...
  Restored /home/chaz/git/github.com_OmniSharp_csharp-language-server-protocol/.build/.build.csproj (in 29.91 sec).
CSC : warning CS8002: Referenced assembly 'Nuke.Common, Version=5.0.2.0, Culture=neutral, PublicKeyToken=null' does not have a strong name. [/home/chaz/git/github.com_OmniSharp_csharp-language-server-protocol/.build/.build.csproj]
CSC : warning CS8002: Referenced assembly 'Rocket.Surgery.Nuke, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' does not have a strong name. [/home/chaz/git/github.com_OmniSharp_csharp-language-server-protocol/.build/.build.csproj]
  .build -> /home/chaz/git/github.com_OmniSharp_csharp-language-server-protocol/.build/bin/Debug/.build.dll

Build succeeded.

CSC : warning CS8002: Referenced assembly 'Nuke.Common, Version=5.0.2.0, Culture=neutral, PublicKeyToken=null' does not have a strong name. [/home/chaz/git/github.com_OmniSharp_csharp-language-server-protocol/.build/.build.csproj]
CSC : warning CS8002: Referenced assembly 'Rocket.Surgery.Nuke, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' does not have a strong name. [/home/chaz/git/github.com_OmniSharp_csharp-language-server-protocol/.build/.build.csproj]
    2 Warning(s)
    0 Error(s)

Time Elapsed 00:00:33.29
It was not possible to find any compatible framework version
The framework 'Microsoft.NETCore.App', version '5.0.0' (x64) was not found.
  - The following frameworks were found:
      6.0.0 at [/home/chaz/.local/local/dotnet-sdk-6.0.100/shared/Microsoft.NETCore.App]

You can resolve the problem by installing the specified framework and/or SDK.

The specified framework can be found at:
  - https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&framework_version=5.0.0&arch=x64&rid=almalinux.8.5-x64

Start by inspecting and running build.sh with the reported .NET SDK versions, then trace the .build/.build.csproj configuration that requests Microsoft.NETCore.App 5.0.0. Done means build.sh completes successfully on .NET 6.0.0 without requiring the missing 5.0.0 framework; the issue does not mention a test file.