fix: gitlab example for trusted publishing

[jrvidal]

I haven't been quite able to make trusted publishing work in GitLab (see npm/cli#8558), but I do think the example is incorrect. id_tokens is not a valid global keyword. It needs to be specified under default or a job. I think a job makes more sense.

Reference:

• https://docs.gitlab.com/ci/yaml/#global-keywords
• https://docs.gitlab.com/ci/yaml/#default
• https://docs.gitlab.com/ci/yaml/#id_tokens

[wraithgar]

Did this approach work for you?

[jrvidal]

Yes:

• Failure
• Success

(The part I haven't made work yet is provenance generation)

[wraithgar]

Yes:

That's very good to hear. Provenance is a separate process, so we can merge this now to get it out there.