Dart 3 support

[mateuszwojtczak]

Motivation

After our project got upgraded to Dart 3, our codemods can't resolve packages.

Changes

Dart version constraint got bumped to >3.0.0 <4.0.0.
Also this broke mockito dependency, so I replaced it with now-standard mocktail.

Release Notes

Added Dart 3 support

Review

See CONTRIBUTING.md for more details on review types (+1 / QA +1 / +10) and code review process.

Please review:

QA Checklist

• Tests were updated and provide good coverage of the changeset and other affected code
• Manual testing was performed if needed
  • Steps from PR author:
  • Anything falling under manual testing criteria outlined in CONTRIBUTING.md

Merge Checklist

While we perform many automated checks before auto-merging, some manual checks are needed:

• A Frontend Frameworks Architecture member has reviewed these changes
• There are no unaddressed comments - this check can be automated if reviewers use the "Request Changes" feature
• For release PRs - Version metadata in Rosie comment is correct

[aviary-wf]

Security Insights

Error scanning for security relevant context

Action Items

• Review PR for security impact; comment "security review required" if needed or unsure
• Verify aviary.yaml coverage of security relevant code

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[evanweible-wf]

Thank you for the PR @mateuszwojtczak! I'm going to merge this into a WIP branch and see if I can get it supporting both Dart 2 and 3 and then I'll get this merged and released

[evanweible-wf]

Should be released as v1.1.0 now, thanks again!