Update README to new format (#476)
Update README to new format (#476)

* Update README to new format

* Update wording

* Update per feedback

(cherry picked from commit 2fe69349dbc7564d8d050b24ee7460c1eeca9ef2)

dotnet/dotnet-docker,MichaelSimons/dotnet-docker,MichaelSimons/dotnet-docker,dotnet/dotnet-docker