adding data source for identity pool provider

.changelog/4181.txt

@@ -0,0 +1,3 @@
+```release-note:new-datasource
+`google_iam_workload_identity_pool_provider`
+```

google/data_source_iam_beta_workload_identity_pool_provider.go

@@ -0,0 +1 @@
+package google

google/data_source_iam_beta_workload_identity_pool_provider_test.go

@@ -0,0 +1 @@
+package google

website/docs/d/iam_workload_identity_pool_provider.markdown

@@ -0,0 +1,41 @@
+---
+subcategory: "Cloud IAM"
+layout: "google"
+page_title: "Google: google_iam_workload_identity_pool_provider"
+sidebar_current: "docs-google-datasource-iam-workload-identity-pool-provider"
+description: |-
+  Get a IAM workload identity pool provider from Google Cloud
+---
+
+# google\_iam\_workload_\identity\_pool\_provider
+
+Get a IAM workload identity provider from Google Cloud by its id.
+
+~> **Warning:** This resource is in beta, and should be used with the terraform-provider-google-beta provider.
+See [Provider Versions](https://terraform.io/docs/providers/google/guides/provider_versions.html) for more details on beta resources.
+
+## Example Usage
+
+```tf
+data "google_iam_workload_identity_pool_provider" "foo" {
+  workload_identity_pool_id          = "foo-pool"
+  workload_identity_pool_provider_id = "bar-provider"
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `workload_identity_pool_id` - (Required) The id of the pool which is the
+    final component of the pool resource name.
+* `workload_identity_pool_provider_id` - (Required) The id of the provider which is the
+    final component of the resource name.
+
+- - -
+
+* `project` - (Optional) The project in which the resource belongs. If it
+    is not provided, the provider project is used.
+
+## Attributes Reference
+See [google_iam_workload_identity_pool_provider](https://www.terraform.io/docs/providers/google/r/iam_workload_identity_pool_provider.html) resource for details of all the available attributes.

website/google.erb

@@ -796,6 +796,10 @@
           <a href="/docs/providers/google/d/iam_workload_identity_pool.html">google_iam_workload_identity_pool</a>
           </li>
 
+          <li>
+          <a href="/docs/providers/google/d/iam_workload_identity_pool_provider">google_iam_workload_identity_pool_provider</a>
+          </li>
+
         </ul>
       </li>
       <li>