Retrieves a list of core definitions.Show details from next link. https://docs.aws.amazon.com/ja_jp/cli/latest/reference/greengrass/list-core-definitions.html
| aws greengrass list-core-definitions \ |
| UpdateCoreDefinition - AWS Greengrass : http://docs.aws.amazon.com/greengrass/latest/apireference/-greengrass-definition-cores.html |