Reformat CHANGELOG.md using standard changelog CLI tool

[mattwynne]

🤔 What's changed?

• reformatted CHANGELOG.md using changelog.

⚡️ What's your motivation?

This tool helps us to manipulate and read changelogs, but it needs to have the file in a standard format that it can read and write.

🏷️ What kind of change is this?

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

♻️ Anything particular you want feedback on?

• I want to see how GitHub renders the changes.
• I know it's a pain how the username links have all been inlined, but I think it's worth it to have a standard tool for working with changelogs. Do you agree?

📋 Checklist:

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

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[codecov]

Codecov Report

Merging #474 (90840cb) into main (4ca5ec0) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #474   +/-   ##
=======================================
  Coverage   81.42%   81.42%           
=======================================
  Files          27       27           
  Lines        2197     2197           
=======================================
  Hits         1789     1789           
  Misses        312      312           
  Partials       96       96           

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