Don't add PR links to changelog

[stefanmatar]

TL;DR

I would like to not include the commit links in the CHANGELOG.md

We would like to take the generated changelog file and publish it onto another platform - for that the commit links don't help.

Detailed design

It would be great if we had an option like generate-pr-links.

Additional information

No response

[chingor13]

Please re-open this on the upstream library: https://github.com/googleapis/release-please