Fix contact validation failure on query data types change (#862)

* add current_timestamp to prevent empty query caching
* add changie log

Author: dementiev27

.changes/unreleased/Fixes-20230804-005817.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Fix contact validation failure on query data types change
+time: 2023-08-04T00:58:17.97704+03:00
+custom:
+  Author: dementiev27
+  Issue: "861"

dbt/include/bigquery/macros/adapters/columns.sql

@@ -0,0 +1,10 @@
+{% macro bigquery__get_empty_subquery_sql(select_sql, select_sql_header=none) %}
+    {%- if select_sql_header is not none -%}
+    {{ select_sql_header }}
+    {%- endif -%}
+    select * from (
+        {{ select_sql }}
+    ) as __dbt_sbq
+    where false and current_timestamp() = current_timestamp()
+    limit 0
+{% endmacro %}