Add missing special member identifiers (#11473)

Author: kustodian

mmv1/third_party/terraform/website/docs/r/bigquery_dataset_iam.html.markdown

@@ -91,6 +91,9 @@ The following arguments are supported:
   * **domain:{domain}**: A G Suite domain (primary, instead of alias) name that represents all the users of that domain. For example, google.com or example.com.
   * **group:{emailid}**: An email address that represents a Google group. For example, [email protected].
   * **iamMember:{principal}**: Some other type of member that appears in the IAM Policy but isn't a user, group, domain, or special group. This is used for example for workload/workforce federated identities (principal, principalSet).
+  * **projectOwners**: A special identifier that represents the Owners of the project of the dataset.
+  * **projectReaders**: A special identifier that represents the Viewers of the project of the dataset.
+  * **projectWriters**: A special identifier that represents the Editors of the project of the dataset.
   * **serviceAccount:{emailid}**: An email address that represents a service account. For example, [email protected].
   * **user:{emailid}**: An email address that represents a specific Google account. For example, [email protected] or [email protected].
 
@@ -177,4 +180,4 @@ The [`terraform import` command](https://developer.hashicorp.com/terraform/cli/c
 
 ```
 $ terraform import google_bigquery_dataset_iam_policy.default projects/{{project_id}}/datasets/{{dataset_id}}
-```
+```