[MNT]: Add copyright information for google's "turbo" colormap?

[anabelle2001]

Summary

The page https://matplotlib.org/stable/project/license.html doesn't mention the "turbo" colormap, which is included in matplotlib, and presumably licensed under Apache 2. That page does seem to mention other color-maps. Should the docs be updated to include the copyright liscence for turbo?

Proposed fix

Possibly, update https://github.com/matplotlib/matplotlib/blob/main/doc/project/license.rst.

[yashisthebatman]

@anabelle2001 could you assign this issue to me

[timhoffm]

We do not assign issues. You are welcome to directly create a pull request.

[QuLogic]

Turbo was added directly by its author in #15275, presumably under the license of Matplotlib, and not anything else. If that is not the case, please chime in here, @mikhailov-work.

[anabelle2001]

Thank you for finding that!

From what i can gather, the only info on the color-map's copyright seems to be within the gists Anton released (for polynomial approximations, etc.), which all start with:

# Copyright 2019 Google LLC.
# SPDX-License-Identifier: Apache-2.0

This came up when I was investigating copyright provenance for a range of colormaps bundled with matplotlib, to reassure my boss that our software wasn't running afoul of any licenses