Upload wheels to scientific-python-nightly-wheels index

[lysnikolaou]

Related to #8199.

In order for this to work we're going to need a secret named PILLOW_NIGHTLY_UPLOAD_TOKEN. @hugovk Did you already create it? If so, what's its name?

[radarhere]

Your original idea was ANACONDA_ORG_UPLOAD_TOKEN, and that was what he requested of aclark4life

[lysnikolaou]

Thanks for the pointer @radarhere! Updated now.

[radarhere]

For my curiosity - can this be removed once Python 3.13 final is released on October 1?