Adds additional user attributes to the user pool schema.
cognitoidentityprovider_add_custom_attributes(UserPoolId,
CustomAttributes)
[required] The user pool ID for the user pool where you want to add custom attributes.
[required] An array of custom attributes, such as Mutable and Name.
svc$add_custom_attributes( UserPoolId = "string", CustomAttributes = list( list( Name = "string", AttributeDataType = "String"|"Number"|"DateTime"|"Boolean", DeveloperOnlyAttribute = TRUE|FALSE, Mutable = TRUE|FALSE, Required = TRUE|FALSE, NumberAttributeConstraints = list( MinValue = "string", MaxValue = "string" ), StringAttributeConstraints = list( MinLength = "string", MaxLength = "string" ) ) ) )