Use a custom Java base image for Mill.
Use a custom Java base image for Mill.

This image is based on the current Debian testing version (bullseye), which has packages for both OpenJDK 11 and libc6 >= 2.29.

Bug: 168138039
Change-Id: I5d4bd2c00884146e96afdedc1fefaa0906d2e5ac

world-federation-of-advertisers/common-jvm,world-federation-of-advertisers/common-jvm