I have a better way to solve exercise 12

I think

rng = np.random.default_rng()
x = rng.random((3, 3, 3))

would be better than

https://github.com/rougier/numpy-100/blob/916e1ecf9544719b49ece6fc135b089988b33058/100_Numpy_exercises_with_hints_with_solutions.md#L96

because the documentation says "[RandomState] should only be used if it is essential to have randoms that are identical to what would have been produced by previous versions of NumPy.".