Same as Issue #349 but on Jenkins. Please upgrade for SDK v5 and v6

[BulldogCTISolutions]

dotnet v2.1 is no longer available. And since it is 2022 and .NET v6 is now in LTS, please upgrade the tool to support the latest GA version of .NET.

[jenkins-agent@csc2cxp00005202 _TI_LUIS_model_deployment_master]$ dotnet-nlu
It was not possible to find any compatible framework version
The framework 'Microsoft.NETCore.App', version '2.1.0' was not found.

• The following frameworks were found:
  5.0.15 at [/usr/share/dotnet/shared/Microsoft.NETCore.App]