Add permissions to conversion_event_categorization_v1

sql/moz-fx-data-shared-prod/google_ads_derived/conversion_event_categorization_v1/metadata.yaml

@@ -25,3 +25,9 @@ bigquery:
     - client_id
     - country
 references: {}
+workgroup_access:
+- role: roles/bigquery.dataViewer
+  members:
+  - workgroup:dataops-managed/external-census
+  - workgroup:google-managed/external-ads-datafusion
+  - workgroup:google-managed/external-ads-dataproc