configure_os: Bump version of polysquare-travis-container to 0.0.43
configure_os: Bump version of polysquare-travis-container to 0.0.43

With this version, local containers now don't depend on proot
at all, which is broken on the travis-ci containerized images.

polysquare/polysquare-ci-scripts,polysquare/polysquare-ci-scripts