GitLab

fix a CI todo and some cleanup

See merge request !25

the blocking issue [Issue 273034](https://gitlab.com/gitlab-org/gitlab/-/issues/273034) is resolved and the used gitlab instance runs a version that has the fix

nightlies and tests are no longer a separate package, as originally intended, as we can now add that information as part of the version

this allows to clean up the packs-nigthly-* and pakcs-test-* packages
which would also accumulate duplicates of all files for each test/nightly run

this way `update_version.sh` and `release_helper.sh` can't easily diverge

for release links this was already done in commits 5d67c555 and 07b31c96

Fix failing "Test Download" scheduled Pipeline job

See merge request !24

upgrade ghc in ci image

See merge request !23