Refactor check against Coursier version-ordering onto Version.Update

[rtyley]

This change just refactors the logic of the check to live on Version.Update (introduced with 13380eb in PR #3145 in August 2023), which feels like a good place for it to belong.

The check for whether our version-updates comply with Coursier version-ordering was added with this PR in January 2020:

• Use Coursier to double-check our version ordering #1210

...the check was supposed to be temporary, until Scala Steward's own Order[Version] was considered battle-tested, but I don't know when we'll decide that's happened!

Notes

current == next is ok?

Since commit 75c08e6, committed directly to main a day later, VersionOrderingConflict has only been raised if current > next - so current == next is fine. There's no further info on why in the commit tho'!

New coursier-versions library

Our Scala Steward check uses coursier.core.Version, which is deprecated since Coursier 2.1.25.

The recommended class is now coursier.version.Version, which is in the newer https://github.com/coursier/versions library created in May 2020.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.85%. Comparing base (50cf04b) to head (f02d697).

Additional details and impacted files

@@                                             Coverage Diff                                              @@
##           replace-update-ForArtifactId-NewerVersions-with-ArtifactUpdateCandidates    #3789      +/-   ##
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- Coverage                                                                     89.86%   89.85%   -0.02%     
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  Lines                                                                          5064     5059       -5     
  Branches                                                                        454      464      +10     
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- Hits                                                                           4551     4546       -5     
  Misses                                                                          513      513              

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