Commit 2f937522aae by Georges Racinet

Merge from default branch for CI config

Heptapod/GitLab CI configuration has been finalized in
the default branch, with some tweaks that will be
interesting in the heptapod branch, too.

But we don't keep the numerous older Mercurial versions
that we don't have to support for Heptapod.

branch : heptapod
Pipeline #1921 failed with stage
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