New agentk authn header
Closes #599 (closed).
Tested GDK with GitLab master
and Authenticate agent requests using Gitlab-Agentk... (gitlab-org/gitlab!157703 - merged). Both configurations work fine.
Also tested Authenticate agent requests using Gitlab-Agentk... (gitlab-org/gitlab!157703 - merged) + just the new header - works fine too.
Edited by Mikhail Mazurskiy