fix: fix cap error in zip code error verification

Author: BennyKitchell

test/Integration/test_zip_lookups_api.py

@@ -74,7 +74,8 @@ def test_lookup_error(self):
 
         with self.assertRaises(Exception) as context:
             self.api.lookup(zip)
-        self.assertTrue("invalid ZIP code" in context.exception.__str__())
+        print(context.exception.__str__())
+        self.assertTrue("invalid zip code" in context.exception.__str__())
 
 
 if __name__ == '__main__':