move noise to install_requires at the setup.cfg

[giancastro]

Keeping noise as a test dependency will make the make_terrain function unavailable.

In the xarray-spatial-feedstock, noise is not a test dependency. Therefore, when installing xarray-spatial using conda, the make_terrain function works.

As you can see in the following image, at the above terminal, I installed xarray-spatial using pip and got the error ModuleNotFoundError: No module named 'noise' when trying to import the make_terrain function. But at the bellow terminal, I installed xarray-spatial using conda and didn't get any errors when trying to import the make_terrain function.