GitLab

Merge branch 'feature/releases_2-7' into 'master'

ref:core/ci-config I just copied the configuration from the 2.6 release into a
corresponding folder for the 2.7 release so that other repositories can test
for these releases.

See merge request [core/ci-config!1]

  [core/ci-config!1]: gitlab.dune-project.org/core/ci-config/merge_requests/1

The test label setup is much too fragile for that, as it turns out...