fix: replace ::set-output with new pattern

[davidjgoss]

🤔 What's changed?

Replace use of ::set-output with new suggested pattern, see https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

⚡️ What's your motivation?

Helps towards cucumber/common#2150.

🏷️ What kind of change is this?

• 🏦 Refactoring/debt/DX (improvement to code design, tooling, documentation etc. without changing behaviour)

📋 Checklist:

• I agree to respect and uphold the Cucumber Community Code of Conduct
• I've changed the behaviour of the code
  • I have added/updated tests to cover my changes.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• Users should know about my change
  • I have added an entry to the "Unreleased" section of the CHANGELOG, linking to this pull request.

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[mpkorstanje]

Merged. If you make a release, Renovate will roll it out.