update docs

Author: barryib

modules/node_groups/README.md

@@ -52,6 +52,7 @@ No requirements.
 | cluster\_name | Name of parent cluster | `string` | n/a | yes |
 | create\_eks | Controls if EKS resources should be created (it affects almost all resources) | `bool` | `true` | no |
 | default\_iam\_role\_arn | ARN of the default IAM worker role to use if one is not specified in `var.node_groups` or `var.node_groups_defaults` | `string` | n/a | yes |
+| ng\_depends\_on | List of references to other resources this submodule depends on | `any` | `null` | no |
 | node\_groups | Map of maps of `eks_node_groups` to create. See "`node_groups` and `node_groups_defaults` keys" section in README.md for more details | `any` | `{}` | no |
 | node\_groups\_defaults | map of maps of node groups to create. See "`node_groups` and `node_groups_defaults` keys" section in README.md for more details | `any` | n/a | yes |
 | tags | A map of tags to add to all resources | `map(string)` | n/a | yes |