Enable merge commits

[petertseng]

@ErikSchierboom and/or @iHiD, it would be preferable (but neither required nor urgent) if you would do me the favour of enabling merge commits for this repo again.

I am not sure when the change was made. It is confirmed that I was able to make a merge commit on 2022-03-06, which is the date of e5f2970, the most recent merge commit made. I know I could not make a merge commit on 2022-07-22, because I reported my inability in #1025. The option says "not enabled for this branch", which means the setting that is forbidding it is a branch-specific setting, not a repo-specific setting.

My records show that in #911 and exercism/rust#979, it was necessary to uncheck the "Require linear history" box.

If this is some new organisation rule that merge commits will not be allowed, just let me know and I'll adjust my workflow accordingly. I've been making do for the time being and I can continue to do so, but if the intent is to make it available to the maintainers that want it, I want it.

[ErikSchierboom]

@petertseng We've enabled merge commits for this repo. Our global policy is to steer people towards using squash merges, but if individual repos want to have merge commits enabled, that's fine.

[iHiD]

(I've just fixed the branch protection on main to allow merge commits too - @ErikSchierboom you might want to update your script to honour the existing setting to require linear history for now?)

[petertseng]

I'll check when processing the next PRs and report back

[ErikSchierboom]

@iHiD No need. We're already respecting the existing linear history setting: https://github.com/exercism/website/pull/2782/files#diff-a8aefcd589358c15bd1202a716871bd7428232fc88a61506ea6694d26c7a2766R27

[petertseng]

was finally able to confirm that merge commits are enabled again, thank you