0.20.3: Set ebs volume size for basic example #65

what

• Setting EBS volume size of 10 for basic example

why

• Terraform apply is failing on

Error: Error creating ElasticSearch domain: ValidationException: EBS storage must be selected for t2.small.elasticsearch

as this is currently being defaulted to 0 https://github.com/cloudposse/terraform-aws-elasticsearch/blob/master/variables.tf#L154

references

• https://github.com/cloudposse/terraform-aws-elasticsearch/blob/master/main.tf#L130