Prepare release: 1.4.0

[github-actions[bot]]

⚡ Merging this PR will automatically create a GitHub Release & publish the package ⚡

This PR was created by the Release stage 1 - create release PR workflow, triggered by @oliver-sanders

Tests:

• Tests last run on master:
• ✔️ Build check passed - see the workflow run (number 39) for more info

Checklist:

• [x] Milestone complete? 0 other open issues/PRs on milestone 1.4.0 at time of PR creation
• [x] Changelog up-to-date?
  • Examine pull requests made since the last release
  • "Released on" date updated? ✔️ 2024-06-18

Next steps:

• @oliver-sanders should request 1 or 2 reviews
• If any further changes are needed, push to this PR branch
• After merging, the bot will comment below with a link to the release (if not, look at the PR checks tab)

[!IMPORTANT] Do not use [skip ci] in commit messages pushed to this PR, as it will prevent the 2nd stage release workflow from running.

[wxtim]

I think that https://github.com/cylc/cylc-rose/issues/319 has a fix synced over to master, and probably ought to be logged: If you agree I'll prep a PR to this PR?

[MetRonnie]

Does anyone know what is going on with the test failure?

[oliver-sanders]

MB, I ran the pre-release tests before Ben's PR was merged so missed this change.

[github-actions[bot]]

✔️ success

Next steps for @oliver-sanders:

• view/edit the GitHub release description as appropriate
• ✔️ Milestone automatically closed

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Comment created by workflow: Release stage 2 - auto publish, run: 50