Update dotnet-runtime-example for 3.0
Update dotnet-runtime-example for 3.0

redhat-developer/s2i-dotnetcore,redhat-developer/s2i-dotnetcore,omajid/s2i-dotnetcore,omajid/s2i-dotnetcore,omajid/s2i-dotnetcore,redhat-developer/s2i-dotnetcore