[scikit-learn] Changes in Travis billing

[Gael Varoquaux]

Travis is changing it's billing strategy:
https://blog.travis-ci.com/2020-11-02-travis-ci-new-billing

Open repositories are getting a free initial set of credit. They invite
open source projects to contact them to benefit from a more liberal
policy.

I suggest that we do the latter, as I fear that we might run out of
credits, and I am quite convinced that we could benefit from the liberal
policy.

Cheers,

Gaël

-- 
    Gael Varoquaux
    Research Director, INRIA		  Visiting professor, McGill 
    http://gael-varoquaux.info            http://twitter.com/GaelVaroquaux