Bump python from 3.8.6-slim to 3.9.0-slim in /docker (from PR #2257)
Bump python from 3.8.6-slim to 3.9.0-slim in /docker (from PR #2257)

Bumps python from 3.8.6-slim to 3.9.0-slim.

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>

mozilla-services/tecken,mozilla-services/tecken,mozilla-services/tecken,mozilla-services/tecken