Update aspnet-owin-tutorial.md
Update aspnet-owin-tutorial.md

Fixing the package name, clarifying Step 2.

yvonnewilson/docs,khorne3/docs,auth0/docs,Annyv2/docs,Catografix/docs,auth0/docs,miparnisari/docs,sandrinodimattia/docs,Annyv2/docs,sandrinodimattia/docs,hamzawi06/docs,auth0/docs,jeffreylees/docs,sandrinodimattia/docs,hamzawi06/docs,khorne3/docs,Annyv2/docs,jeffreylees/docs,yvonnewilson/docs,yvonnewilson/docs,jeffreylees/docs,Catografix/docs,hamzawi06/docs,Catografix/docs,khorne3/docs