Add new stream for pr-files

[leomattic]

Priority

Non-urgent, nice to have one day.

Description of change

It would be fun to have the number of lines added and deleted per pr. This would allow us to aggregate them by repo or team and see the ebbs and flows of our development.

I naively tried to add it in the pull requests themselves:

• https://github.com/Automattic/nosara/pull/8897

It looks like we have to dig a little deeper. The best would be to get the details of each commit but that sounds too expensive as there can be many per pull request.

Another option would be to get the details of each file in a pul request. It looks like we can use the endpoint in a similar way we are already doing with pr_commits to have a new stream pr_files.

https://docs.github.com/en/rest/pulls/pulls?apiVersion=2022-11-28#list-pull-requests-files

https://api.github.com/repos/OWNER/REPO/pulls/PULL_NUMBER/commits
https://api.github.com/repos/OWNER/REPO/pulls/PULL_NUMBER/files

Manual QA steps

Note: I have not tested this, it's my first attempt and should be taken more like pseudo code than anything else.

Risks

Rollback steps

• revert this branch

[joaopamaral]

This is a great contribution @leomattic! 🚀 Thank you so much!
I've only added a small change to fix the schema (I ran a local test).
cbeb336

[leomattic]

Thank you for all the help @joaopamaral !!
If you test it and it works with the updates then I would love to merge it!! 🥳

How would it work btw? will it detect it's missing data for the existing PRs and do a backfill or will the data be available only for new PRs?