Replace deprecated ::set-output

[nodeg]

🤔 What's changed?

As per the deprecation warning and explanation at https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

⚡️ What's your motivation?

See cucumber/common#2150

🏷️ What kind of change is this?

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

♻️ Anything particular you want feedback on?

Is the changelog entry fine this way?

📋 Checklist:

• I agree to respect and uphold the Cucumber Community Code of Conduct
• 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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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.87%. Comparing base (153db4e) to head (fa132dd).
Report is 29 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #681      +/-   ##
==========================================
- Coverage   83.21%   77.87%   -5.34%     
==========================================
  Files          28       41      +13     
  Lines        3413     4050     +637     
==========================================
+ Hits         2840     3154     +314     
- Misses        458      778     +320     
- Partials      115      118       +3     

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