Use debian:11 as the base image
Bump from debian:10 to debian:11 to match the OS of the current
production deployment server.
Side effects:
-
exp/Dockerfile.php-base:
Populate /etc/apt/sources.list.d/ and /etc/apt/trusted.gpg.d/ with files
copied from deploy1003.eqiad.wmnet. -
exp/setup-certs:
The version of etcd that comes with Debian 11 requires a certificate
with a Subject Alternative Name field, so use DNS:db.