Updated changelog for 2.8

changed milestone to %DUNE 2.8.0

added 18 commits

• 199c023c...da9f1859 - 17 commits from branch master
• d6a29d3e - Updated changelog for 2.8

Compare with previous version

enabled an automatic merge when the pipeline for d6a29d3e succeeds

canceled the automatic merge

merged

mentioned in commit 31f919a1

picked the changes into the branch cherry-pick-31f919a1 with commit 3e34fee8

mentioned in commit 3e34fee8

mentioned in merge request !1003 (merged)