"About Us" page refers to BSD license rather than Creative Commons

[timw6n]

As above, the about us page (source https://github.com/holoviz/colorcet/blob/master/doc/about.rst) looks to be referencing the wrong license.

Should probably be changed to say CC-BY there, to match the LICENSE.txt file in the repository.

Suspect the text referencing BSD has crept in as boilerplate from other Holoviz projects.

[jbednar]

Good catch! Interested in making a PR to fix that?

[timw6n]

Done. Not really used .rst files before so hope I've got the syntax correct. #101