upgrade to ML.NET 1.5.1

[ganik]

No description provided.

[klesouza]

Sorry to step into this PR. I was just curious to know if you guys have plans to merge this PR soon. ML.NET 1.5.1 has some fixes I was interested to see available in NimbusML.

[ganik]

Sorry to step into this PR. I was just curious to know if you guys have plans to merge this PR soon. ML.NET 1.5.1 has some fixes I was interested to see available in NimbusML.

@klesouza Which fixes you are looking for in ML.NET ?

[klesouza]

@ganik, I run into some problems regarding handling of categorical features in LightGBM. I looked around in ML.NET repo and found fixes for that in later versions (dotnet/machinelearning#5048)
The error I'm getting is: 'Categorical split features is zero length'

[ganik]

@klesouza there are few regressions we found in ML.NET 1.5.1 that need to be fixed. They will come in next ML.NET release. So we are targeting it. Also fyi there is no active development on NimbusML anymore. Only critical bug fixes/patches.