Arviz: Add `Matplotlib` framework classifier to `setup.py`

[hectormz]

Matplotlib now has a trove classifier on pypi. We can add:

classifiers = [
    'Framework :: Matplotlib',
    ]

to arviz's setup.py to acknowledge that it is part of Matplotlib ecosystem.

I believe that arviz currently doesn't have any classifiers (there are many!). We could add something like the following to setup.py:

classifiers = [
    'Framework :: Matplotlib',
    'Intended Audience :: Science/Research',
    'License :: OSI Approved :: Apache Software License'
    'Programming Language :: Python',
    'Programming Language :: Python :: 3',
    'Programming Language :: Python :: 3.5',
    'Programming Language :: Python :: 3.6',
    'Programming Language :: Python :: 3.7',
    'Topic :: Scientific/Engineering :: Visualization',
    ]

I'm not sure if you would say if arviz is:

'Development Status :: 5 - Production/Stable',

or

'Development Status :: 4 - Beta',

There may be thoughts on other classifiers to add, but I can quickly put together a PR for this

[OriolAbril]

We are definitely still beta!

Also, we are not as strict as NEP 29 recommends but python versions should be 3.6, 3.7 and 3.8

Possible ideas, Intended Audience :: Education? I'm not really sure about the scope of the classifiers

[hectormz]

@OriolAbril I figured beta, but thought it'd be best for a maintainer to say so!

I realized I wasn't sure which versions arviz supports but I grabbed this from README:

ArviZ is tested on Python 3.5, 3.6 and 3.7, and depends on NumPy, SciPy, xarray, and Matplotlib.

Should that be updated to 3.6, 3.7, 3.8 as well?

I don't see why arviz couldn't be filed as Education. There's quite a lot of options if someone is motivated to read through them all. 😀

[OriolAbril]

Should that be updated to 3.6, 3.7, 3.8 as well?

Yes, we recently updated CI builds, we don't run tests on 3.5 anymore

[hectormz]

@OriolAbril @canyon289 @ahartikainen @aloctavodia and any others, do you have any additional thoughts on other itemz worth adding here?

Otherwise I can make a PR with additions @OriolAbril and I have discussed.

[ahartikainen]

https://pypi.org/search/?c=Topic+%3A%3A+Scientific%2FEngineering+%3A%3A+Mathematics
https://pypi.org/search/?c=Topic+%3A%3A+Scientific%2FEngineering+%3A%3A+Visualization

?

ref. https://pypi.org/classifiers/

[aloctavodia]

About the topic, I guess we can have the generic one, and then two specifics

Topic :: Scientific/Engineering
Topic :: Scientific/Engineering :: Mathematics
Topic :: Scientific/Engineering :: Visualization

[hectormz]

Sure I can draft a PR and see if it's satisfactory