Update dependencies.

[rosiel]

GitHub Issue: (link)

Update dependency versions to newer modules.

What does this Pull Request do?

This shouldn't do much except

• install migrate_plus v6 which is functionally the same as 5 according to the release notes
• install a newer codesniffer if you're ever using this module's require-dev's.

How should this be tested?

It should still install through composer, and the site should function as usual. I tested to the best of my ability; the migrate module seems to be working with the old migrations still.

Documentation Status

• Does this change existing behaviour that's currently documented? no
• Does this change require new pages or sections of documentation? no
• Who does this need to be documented for? no-one
• Associated documentation pull request(s): ___ or documentation issue ___

Additional Notes:

Any additional information that you think would be helpful when reviewing this
PR.

Interested parties

Tag (@ mention) interested parties or, if unsure, @Islandora/8-x-committers

[rosiel]

needs specific migration testing, since migrate syntax can be fragile between versions.

[jordandukart]

@rosiel are there any bumps in here that are still needed given that time has passed, things have already been bumped in the composer.json a bit and the fact that this is conflicting now?

[rosiel]

🤦 another git rebase nightmare. Sorry. I'll try again (and most of them have been done, you're right.)