fix(ci): use up-to-date npm version for Trusted Publishers

[cyclimse]

Summary

What's changed?

• Bump ubuntu runners
• Bump npm version in publish workflow

Why do we need this?

• Release job for v0.4.18 is still not passing :/
• Seems that npm doesn't attempt to use Github OIDC at all
• See logs: https://github.com/scaleway/serverless-scaleway-functions/actions/runs/20093290896/job/57645510011

How have you tested it?

• Create dummy CI jobs to check npm version

=> As you can see, even bumping to use 24.04 Ubuntu doesn't give us npm 11.5+ so we have to further run a npm i -g npm@latest kind of thing

Checklist

• I have reviewed this myself
• There is a unit test covering every change in this PR
• I have updated the relevant documentation

Details