Updated Coinbase (#3259)
Updated Coinbase (#3259)

Update doc to remove "authy" portion of the URL as they support multiple software options, not just Authy.
rugk/twofactorauth,rj175/twofactorauth,bceasydns/twofactorauth,jdavis/twofactorauth,Jawshy/twofactorauth,Jawshy/twofactorauth,jdavis/twofactorauth,Jawshy/twofactorauth,vgarmash/twofactorauth,rugk/twofactorauth,Nitrokey/dongleauth,vgarmash/twofactorauth,bceasydns/twofactorauth,bceasydns/twofactorauth,jdavis/twofactorauth,bjorno/twofactorauth,vgarmash/twofactorauth,cez81/twofactorauth,rj175/twofactorauth,bjorno/twofactorauth,rugk/twofactorauth,Nitrokey/dongleauth,cez81/twofactorauth,Nitrokey/dongleauth,bjorno/twofactorauth,cez81/twofactorauth,rj175/twofactorauth,Jawshy/twofactorauth