Builds the otpauth://totp/ URI (Google's Key Uri Format): the issuer on
the label and as a parameter, the secret unpadded, and the algorithm,
digits and period always written out.
Parameters
spec: OtpauthSpec
{ issuer, account, secret, algorithm, digits, period }
Builds the
otpauth://totp/URI (Google's Key Uri Format): the issuer on the label and as a parameter, the secret unpadded, and the algorithm, digits and period always written out.