Fix mistaken references to "instagram" in linkedin-auth
Fix mistaken references to "instagram" in linkedin-auth

It looks like a previous revision of the linkedin-auth Cloud Functions sample used Instagram instead of LinkedIn; there were a few references to "instagram" still hanging around the code.
firebase/functions-samples,Kevded/functions-samples,firebase/functions-samples,firebase/functions-samples,firebase/functions-samples,Kevded/functions-samples,Kevded/functions-samples,Kevded/functions-samples