Similar to Zuul (I71182e9d3e6e930977a9f983b37743ee3300ec91), the base
images have updated to Bullseye.
This updates various things to get a building Bullseye image.
We have upgrade to 3.9-based images here because OpenDev builds ARM64
wheels for a bullseye+arm64 combo, which we use to speed up the ARM64
cross-build (we do not have any repository of <3.7|3.8>+bullseye ARM64
wheels, so it makes it difficult to use these combos as the
cross-build can take a very long time)
Depends-On: https://review.opendev.org/c/openstack/diskimage-builder/+/806318
Change-Id: I21cfbd3935e48be4b92591ea36c7eed301230753
f5d015c883