ci(labeler): call the QAtlasHub reusable workflow instead of gh pr edit

[sotashimozono]

Warning

Merging this cuts a release. This repo is public, so AutoRegister answers the
Project.toml bump on main with a @JuliaRegistrator register comment → General registry.
The bump is not optional (VersionCheck runs on every PR by design), so v0.4.1 → v0.4.2 is
the price of a CI-only change here. Hold the merge if you do not want v0.4.2 published.

Description

gh pr edit --add-label reads the pull request over GraphQL, and GitHub now answers that query
with the Projects-classic sunset notice (repository.pullRequest.projectCards); gh reports it
as an error and exits 1. The hand-rolled PRLabeler.yml therefore fails on a deprecation message
that has nothing to do with labelling — measured on lab-sotashimozono/FunctionMeasures.jl, green
on 07-27 and red on 07-28, with no change to the workflow.

40 repos across lab-sotashimozono / QAtlasHub / sotashimozono carried that copy. This replaces
it with the thin caller of the reusable workflow that already serves 4 repos, so the
implementation lives once in QAtlasHub/.github (labeler.yml@v1,
fixed in QAtlasHub/.github#18) and the next breakage is one commit there instead of one PR per repo.

Behaviour is preserved: same six labels, same colours (created on demand), same
Type-of-Change checkbox parsing, and breaking is still removed when its box is unticked.
A public repo takes the workflow's default runner (ubuntu-latest), so the caller needs no inputs.

Type of Change

• 🧰 Maintenance (chore)

Proposed Changes

• .github/workflows/PRLabeler.yml → thin caller of QAtlasHub/.github/.github/workflows/labeler.yml@v1
• Project.toml v0.4.1 → v0.4.2 (VersionCheck runs on every PR, deliberately, so a
  workflow-only change still needs the bump)

Usage or Results

This PR labels itself: the chore box above is what the reusable workflow reads, so a green
PR Labeler check plus a chore label on this PR is the end-to-end proof that the replacement
works in this repo.

[JuliaRegistrator]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[github-actions]

📚 Docs preview: https://QAtlasHub.github.io/ParallelManager.jl/previews/PR30/

(updates on each push to this PR)