onionmasq container quick fix

cherry-picked from !314 so that CI is functional without the need to wait for !314

I've tested this by adding temporarily b2043f35 to this MR, tagging and pushing the commit and by manually building the container from the web UI. The resulting CI job can be found here: https://gitlab.torproject.org/tpo/core/onionmasq/-/jobs/762899. In the meanwhile I've reverted b2043f35.

changed milestone to %VPN pre-alpha 08

requested review from @cve

assigned to @cyberta

approved this merge request

requested review from @micah and removed review request for @cve

mentioned in commit d475e39f

merged