bowling: negative test uses positive value

In the "bowling/bowling_test.py" file there is a test that is testing a positive integer where (in the canonical data) it should be testing -1.

```python
def test_rolls_cannot_score_negative_points(self):
 with self.assertRaisesWithMessage(ValueError):
 self.game.roll(11)
```

That last line should read:

```python
 self.game.roll(-1)
```