start_date and end_date casting fix (#22)

Author: fivetran-joemarkiewicz

macros/get_metric_sql.sql

@@ -143,8 +143,8 @@ joined as (
 bounded as (
     select 
         *,
-        {% if start_date %} '{{ start_date }}' {% else %} min(case when has_data then period end) over () {% endif %} as lower_bound,
-        {% if end_date %} '{{ end_date }}' {% else %} max(case when has_data then period end) over () {% endif %} as upper_bound
+        {% if start_date %}cast('{{ start_date }}' as date){% else %} min(case when has_data then period end) over () {% endif %} as lower_bound,
+        {% if end_date %}cast('{{ end_date }}' as date){% else %} max(case when has_data then period end) over () {% endif %} as upper_bound
     from joined 
 ),