Updating bq config doc (#5756)

website/docs/reference/resource-configs/bigquery-configs.md

@@ -395,6 +395,12 @@ select * from {{ ref('another_model') }}
 
 </File>
 
+You can create a new label with no value or remove a value from an existing label key. 
+
+A label with a key that has an empty value can also be [referred](https://cloud.google.com/bigquery/docs/adding-labels#adding_a_label_without_a_value) to as a tag in BigQuery. However, this should not be confused with a [tag resource](https://cloud.google.com/bigquery/docs/tags), which conditionally applies IAM policies to BigQuery tables and datasets. Find out more in [labels and tags](https://cloud.google.com/resource-manager/docs/tags/tags-overview). 
+
+Currently, it's not possible to apply IAM tags in BigQuery, however, you can weigh in by upvoting [GitHub issue 1134](https://github.com/dbt-labs/dbt-bigquery/issues/1134).
+
 ### Policy tags
 BigQuery enables [column-level security](https://cloud.google.com/bigquery/docs/column-level-security-intro) by setting [policy tags](https://cloud.google.com/bigquery/docs/best-practices-policy-tags) on specific columns.