* Disable manylinux only tests on Travis CI ppc64le Those tests are taking too much disk space for the Travis CI runner right now. c.f. https://travis-ci.community/t/running-out-of-disk-space-quota-when-using-docker-on-ppc64le/11634 * Use focal to run aarch64/ppc64le/s390x jobs on Travis CI This removes allow_failures from the Travis CI s390x job * Use `focal` distribution for all Travis CI configurations * Revert "Disable manylinux only tests on Travis CI ppc64le" This reverts commit d0a09c689c058985c7dcb60b1e11a85a7bfce5e0. * Skip test_manylinuxXXXX_only on Travis CI ppc64le * Add a comment on why test_manylinuxXXXX_only test is skipped