chore: wrap pgtap in transaction

Author: sweatybridge

migrations/tests/test.sql

@@ -1,10 +1,10 @@
 -- Create all extensions
 \ir extensions/test.sql
 
-CREATE EXTENSION IF NOT EXISTS pgtap;
-
 BEGIN;
 
+CREATE EXTENSION IF NOT EXISTS pgtap;
+
 SELECT plan(33);
 
 \ir fixtures.sql