Ensure logs use colored output

[jamietanna]

I've noticed that - at least in a couple of jobs I've looked at - we don't currently log with coloured output

It'd be great when reading the log lines to see the same colours that Renovate CLI users see locally, too

(Noticed as part of looking into #969)

[viceice]

reverted in

• fix: removed tty allocation in docker run #1056