`matplotlib` dependency should be on `matplotlib-base`

[paskino]

CIL is relaxing the dependency on matplotlib to be matplotlib-base. The difference between the packages is that matplotlib depends on matplotlib-base and has the additional dependency on pyside6. See,

• https://github.com/conda-forge/matplotlib-feedstock/blob/f1a4aa1cb6f35ebb710e5d2768b2b3f67425c2f9/recipe/meta.yaml#L61-L72
• https://github.com/conda-forge/matplotlib-feedstock/blob/f1a4aa1cb6f35ebb710e5d2768b2b3f67425c2f9/recipe/meta.yaml#L88-L97
• see Use matplotlib-base instead of matplotlib CIL#2031

It is reasonable to swap the dependency to matplotlib with matplotlib-base in this recipe too.