The previous repository we used removed the binaries for mvn 3.9.2, which broke our docker build. It looks like `archive.apache.org` keeps artifacts longer and hopefully won't break our docker build again soon.
We're verifying the checksum of the gradle archive we fetch before building the docker image with it. I forgot to update that checksum in #2690
We were previously relying on mvn 3.6.3 which has reached EOL.