add google_compute_reservation data source docs

mmv1/third_party/terraform/website/docs/d/compute_reservation.html.markdown

@@ -0,0 +1,46 @@
+---
+subcategory: "Compute Engine"
+description: |-
+  Provide access to a Reservation's attributes
+---
+
+# google\_compute\_reservation
+
+Provides access to available Google Compute Reservation Resources for a given project.
+See more about [Reservations of Compute Engine resources](https://cloud.google.com/compute/docs/instances/reservations-overview) in the upstream docs.
+
+```hcl
+data "google_compute_reservation" "reservation" {
+  name = "gce-reservation"
+  zone = "us-central1-a"
+}
+
+resource "google_compute_reservation" "test" {
+  name = "gce-reservation"
+  zone = "us-central1-a"
+  project = "PROJECT_ID"
+
+
+  specific_reservation {
+    count = 3
+    instance_properties {
+      min_cpu_platform = "Intel Cascade Lake"
+      machine_type     = "n2-standard-2"
+    }
+  }
+}
+```
+
+## Argument Reference
+
+The following arguments are supported:
+
+* `name` (Required) - The name of the Compute Reservation.
+* `zone` (Required) - Zone where the Compute Reservation resides.
+* `project` (Optional) - Project from which to list the Compute Reservation. Defaults to project declared in the provider.
+
+## Attributes Reference
+
+See [google_compute_reservation](https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/compute_reservation) resource for details of the available attributes.
+
+