Upgrade to numpy 2.0

[raphaeltimbo]

We need to upgrade ross to work with numpy 2.0.
This means that we will have to change our test matrix so that we will only support python >= 3.9.

[jguarato]

For the record:

It appears that in NumPy 2.0.0, the representation repr of NumPy scalars changed, causing conflicts when running pytest.

See: NumPy 2.0.0 Release Notes

Possible solutions:

1. Create a conftest.py file with a pytest hook to modify options for doctests:

   def pytest_configure(config):
       np.set_printoptions(legacy='1.25')

   This will ensure compatibility with the previous NumPy behavior.

2. Update all doctests to align with the new NumPy behavior.

[ross-bott]

Hi there!
I have marked this issue as stale because it has not had activity for 45 days.
Consider the following options:

• If the issue refers to a large task, break it in smaller issues that can be solved in
  less than 45 days;
• Label the issue as wontfix or wontfix for now and close it.