The property `UpdatedBy` of `AWS::SecurityHub::AutomationRule.NoteUpdate` should be string, not object

[dafujii]

The document says that UpdatedBy is Type: String.

http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-securityhub-automationrule-noteupdate.html#cfn-securityhub-automationrule-noteupdate-updatedby

UpdatedBy
    The principal that updated the note.
    Type: String
    Pattern: .*\S.*
    Required: Yes

But goformation says that UpdatedBy is object.

https://github.com/awslabs/goformation/blob/master/cloudformation/securityhub/aws-securityhub-automationrule_noteupdate.go#L21 (created in #601.)