Usage
myTarAuth(
  login = getOption("rmytarget.login"),
  grant_type = "client_credentials",
  client_id = getOption("rmytarget.client_id"),
  client_secret = getOption("rmytarget.client_secret"),
  agency_client_name = NULL,
  code_grant = getOption("rmytarget.code_grant_auth"),
  token_path = myTarTokenPath()
)