Update dotnet-sdk-user-guide.md

[czd890]

Update docs for .NET SDK

What's the purpose of this PR

XXXXX

Which issue(s) this PR fixes:

Fixes #

Brief changelog

XXXXX

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recheck

[codecov-commenter]

Codecov Report

Merging #3887 (95f902b) into master (2e2919d) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #3887   +/-   ##
=========================================
  Coverage     50.14%   50.14%           
  Complexity     2479     2479           
=========================================
  Files           485      485           
  Lines         14984    14984           
  Branches       1532     1532           
=========================================
  Hits           7514     7514           
  Misses         6938     6938           
  Partials        532      532           

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[nobodyiam]

the current dotnet document was targeted to the old version, I think your change is targeted to the new dotnet-core version?

I guess the dotnet-core version is more popular now, so I'm thinking we may need to add the document for dotnet-core version? How do you think? cc @pengweiqhca

[pengweiqhca]

I think should merge and then change to dotnet-core.