chore: setup 5.x auto release

[mweberxyz]

See #3110 for details. Both should merge at the same time.

This relates to...

#3103

Rationale

Add 5.x specific deployment logic to v5.x branch

Changes

Backport release workflow and release script from main, ensure change logs are generated against previous 5.x release, ensure tag on npm publish is five, and remove publish-undici-types workflow (now taken care of during release workflow)

Notes

Assuming the release environment is set to Protected branches only, branch protection rules must be added for v5.x branch, as this change will enable automated release on push.

Alternatively (for added security) -- the release environment should be limited to exactly the main or v5.x branch, in addition to adding branch protection rules to v5.x.

If the following protections are added:

Then this is what a malicious branch and workflow run would look like, with the release blocked:
https://github.com/mweberxyz/nodejs-undici/commits/malicious/
https://github.com/mweberxyz/nodejs-undici/actions/runs/8674454300

Status

• I have read and agreed to the Developer's Certificate of Origin
• Tested
• Review ready