Upgrade camoproxy to 2.4.6
What
Upgrade go-camo to 2.4.6
This MR updates to the latest version and uses the --no-debug-vars switch.
Why
Fixes https://gitlab.com/gitlab-org/gitlab/-/issues/373393#note_1616358715
The endpoint doesn't reveal any secret data right now but it could (accidentally) do it in the future so we're updating.
Edited by Dominic Couture