db cluster parameter group requires property parameters

[Guslington]

At the moment if no properties are defined in config resource tries to create with no parameters.

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-rds-dbclusterparametergroup.html#cfn-rds-dbclusterparametergroup-parameters

the condition probably needs to be on the whole resource to not render or provide some sensible default parameters.

[aaronwalker]

@Guslington default could be

cluster_parameters:
  timezone: "UTC"

Since ALL Databases should be running in UTC 😉

[Samseppiol]

Fixed in: #4