Update pypi owner for this package

(cc @tacaswell )
Current on pypi (https://pypi.org/project/ipympl/) this project lists the following maintainers:

@ianhi
@blink1073
@SylvainCorlay
@martinRenou

I'm not sure which one of us is the owner, but it is not me.


For long term health of the project I think that the owner on pypi should be the matplotlib organization as is the case for the main matplotlib project:


Start on the ipympl project page on PyPI and compare its listed maintainers with the matplotlib project. Confirm which PyPI account or organization should own the package and what access is required; done means the matplotlib organization is listed as the owner without disrupting the existing maintainers.

Written by the indexing model from the issue text.