build-website GitLab CI job fails: "413 Request Entity Too Large" when trying to upload artifacts to coordinator

Impact: At the moment this is not a huge blocker, more like a small time sink. But it'll block releasing Tails early January, or earlier in case we have to publish an emergency release.

Example: https://gitlab.tails.boum.org/tails/tails/-/jobs/170830

Created cache
Uploading artifacts for successful job
07:11
Uploading artifacts...
config/chroot_local-includes/usr/share/doc/tails/website: found 7362 matching artifact files and directories 
ERROR: Uploading artifacts as "archive" to coordinator... 413 Request Entity Too Large  id=170830 responseStatus=413 Request Entity Too Large status=413 token=glcbt-64
FATAL: too large