Travis CI Usage

[ewdurbin]

Just a check-in from the Python Software Foundation regarding the Travis-CI plan that supports the s390x and ppc64le architecture builds for this project.

Travis-CI is going to be raising prices on their plans soon, so I'm verifying a few things to inform if we move from monthly-to-annual billing to delay the cost increase (at least for a year):

1. Is Travis-CI still required for this project's CI/build needs?
2. Does the project anticipate being able to move off of Travis-CI at any point, particularly before March 2026?

[mayeut]

This project could probably drop Travis-CI & move to QEMU on GitHub Actions with a reduced test set only on push.

As long as manylinux and/or cibuildwheel do need it, this project is better off using Travis CI with native builds.

Now that aarch64 have been moved from Travis-CI to GHA, if possible, I think going with the "Usage based" plan of Travis-CI would better fit this project (s390x & ppc64le are 0 credits builds: https://docs.travis-ci.com/user/billing-overview/#partner-queue-solution) and would allow parallel builds which is not possible with the current plan (was reduced from 2 to 1 sometime in the past months/years).