[gimp] (7 commits) Non-fast-forward update to branch wip/schumaml/CI-add-distcheck-job

[Michael Schumacher <schumaml src gnome org>]

The branch 'wip/schumaml/CI-add-distcheck-job' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  58638ee... build: add an additional distcheck step to .gitlab-ci.yml
  e8a3321... build: allow the distcheck job to fail
  84b5dfe... .gitlab-ci.yml: remove trailing whitespace

Commits added to the branch:

  1c1e3de... app, configure: depend on babl-0.1.78 (*)
  dac5718... autotools,app: depend on GEGL 0.4.24 (*)
  68d2151... configure.ac: bump versions for the 2.10.20 release (*)
  de65e92... configure.ac: post-release version bump to 2.10.21 (*)
  449e44b... build: add an additional distcheck step to .gitlab-ci.yml
  d473a11... build: allow the distcheck job to fail
  d15cc72... .gitlab-ci.yml: remove trailing whitespace

(*) This commit already existed in another branch; no separate mail sent