feat(bigquery): update the api

#### bigquery:v2

The following keys were added:
- schemas.DatasetList.properties.datasets.items.properties.externalDatasetReference (Total Keys: 2)

Author: yoshi-automation

docs/dyn/bigquery_v2.datasets.html

@@ -483,6 +483,10 @@ <h3>Method Details</h3>
         &quot;datasetId&quot;: &quot;A String&quot;, # Required. A unique ID for this dataset, without the project name. The ID must contain only letters (a-z, A-Z), numbers (0-9), or underscores (_). The maximum length is 1,024 characters.
         &quot;projectId&quot;: &quot;A String&quot;, # Optional. The ID of the project containing this dataset.
       },
+      &quot;externalDatasetReference&quot;: { # Configures the access a dataset defined in an external metadata storage. # Output only. Reference to a read-only external dataset defined in data catalogs outside of BigQuery. Filled out when the dataset type is EXTERNAL.
+        &quot;connection&quot;: &quot;A String&quot;, # Required. The connection id that is used to access the external_source. Format: projects/{project_id}/locations/{location_id}/connections/{connection_id}
+        &quot;externalSource&quot;: &quot;A String&quot;, # Required. External source that backs this dataset.
+      },
       &quot;friendlyName&quot;: &quot;A String&quot;, # An alternate name for the dataset. The friendly name is purely decorative in nature.
       &quot;id&quot;: &quot;A String&quot;, # The fully-qualified, unique, opaque ID of the dataset.
       &quot;kind&quot;: &quot;A String&quot;, # The resource type. This property always returns the value &quot;bigquery#dataset&quot;