Remove GPG signing color to allow pilot runners to execute package jobs

Why was this MR needed?

Emitting ANSII colors in jobs causes pilot runners to break: Pilot runners: Emitting ANSII colors in a job c... (step-runner#414 - closed) • Romuald Atchadé • 18.11

This MR removes these colors from the package jobs allowing us to switch over the gitlab-runner jobs to pilot runners.

There's still two issues remaining but both jobs are marked as allowed to fail:

• gitlab-advanced-sast - Pilot runners: Error response from daemon: cont... (step-runner#413 - closed) • Cameron Swords • 18.11
• integration test (docker, steps) - Pilot runners: integration test (docker, steps)... (step-runner#415 - closed) • Arran Walker • 18.11

We might be okay to leave them like this for now to avoid further changes. Ideally we won't have to do any changes but blocking pilot runners because of ANSII colors seems suboptimal.

What's the best way to test this MR?

Nothing will change. This was tested at !6484 (closed)

What are the relevant issue numbers?

Related to Deploy pilot runner (gitlab-org#20469) • Georgi N. Georgiev | GitLab, Joe Burnett