Fix bool coercion to 0/1 (#4512)

* Fix bool coercion

* Fix unit test

automatic commit by git-black, original commits:
  417ccdc

core/dbt/clients/agate_helper.py

@@ -18,9 +18,7 @@ class Number(agate.data_types.Number):
     # i.e. do not cast True and False to numeric 1 and 0
     def cast(self, d):
         if type(d) == bool:
-            raise agate.exceptions.CastError(
-                'Do not cast True to 1 or False to 0.'
-            )
+            raise agate.exceptions.CastError("Do not cast True to 1 or False to 0.")
         else:
             return super().cast(d)
 
@@ -53,7 +51,7 @@ def build_type_tester(
 ) -> agate.TypeTester:
 
     types = [
-        Number(null_values=('null', '')),
+        Number(null_values=("null", "")),
         agate.data_types.Date(null_values=('null', ''),
                               date_format='%Y-%m-%d'),
         agate.data_types.DateTime(null_values=('null', ''),