updated readme with new option name
updated readme with new option name

dragon-air/intl-tel-input,dragon-air/intl-tel-input,Bluefieldscom/intl-tel-input,jackocnr/intl-tel-input,nlwillia/intl-tel-input,nlwillia/intl-tel-input,jackocnr/intl-tel-input,Bluefieldscom/intl-tel-input