[Chore] prepare 0.4.0 release of morley-prelude

Description

Problem: we have some new changes in morley-prelude that we'd like to use in our projects. In particular we have dropped the use of 'mixins' and 'base' in favor of 'base-noprelude' and re-exported 'Data.Kind.Type'.

Solution: update *.cabal and package.yaml for the new version. Additionally, bump the licensing year.

Related issue(s)

None

✅ Checklist for your Merge Request

Related changes (conditional)

• Tests (see short guidelines)

  • If I added new functionality, I added tests covering it.
  • If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.

• Documentation

  • I checked whether I should update the docs and did so if necessary:
    • Root README and other README.md files
    • Haddock
    • docs/
  • I updated changelog files of all affected packages released to Hackage if my changes are externally visible.

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