Wrong parameter return_to in logout

[marcfx]

Based on auth.js doc, in logout should be used parameter returnTo and not return_to.

auth0-javascript-samples/01-Login/app.js

Line 75 in 77eba03

 return_to: window.location.origin 

[Steve Hobbs]

Thanks @marcfx. This sample has since been rewritten and this change has been incorporated into that rewrite.