Update header copyright to 2024

[Lestropie]

Necessary update for successful merging of any new changes to master.

[daljit46]

Can we merge this into dev too?

[Lestropie]

Can we merge this into dev too?

Normally I'd opt to do this as a regular merge of master into dev. However with cmake & clang-format being on dev now this is a very unclean merge. So I think maybe we'll just redo the copyright update on dev separately, and any fixes on master that need to make their way to dev (which is not all of them) can be individually merged / cherry-picked.

[jdtournier]

We'll need to do the merge properly at some point anyway, otherwise we simply won't be able to merge back to master when we eventually release. I reckon it's best to do the messy work now, otherwise it'll only get worse over time. Personally, I think we need to do a merge of master back to dev back now.

[Lestropie]

It's possible that for something like update_copyright, running separately on each branch prior to merging might give git merge a bit of a helping hand in terms of reducing the scope of conflicts. I'll have to check the other PRs that have since gone to master to see the scope of those. A naive git merge produced a much larger conflict than what I would have expected, probably due to differences in indentation. Manually cherry-picking each PR onto dev and then accepting local in the merge conflict might be the way to go, to make sure that no desired changes are lost in the merge.