.Net core support (linux)

[GoEddie]

do it!

[lastlink]

• well I have a deploy that works using dotnet core and github actions see github action using dotnet core #58. But this isn't enough to close this ticket.

[lastlink]

• github actions is in the correct direction. 07302020 - Added UnitTest Core version #54 isn't tested and should not be merged.
• also comment from TSQLT install rr-wfm/MSBuild.Sdk.SqlProj#49 for tsql testing. it appears w/ already existing tools that if we use a tsql dacpac then it may be possible to publish on dotnet core.
• I think this should be tested against sql server 2019 docker image for best results. But if it builds in github actions and generates coverage then this ticket can be closed. I may look into this in the next few weeks if it's not too big a task.