Update the check_for_changes job in CI

[cswartzvi]

As per my conversation with @elijahbenizzy in #1121 I have updated the check_for_changes job in the CI configuration file so that it compares against main (vice the previous commit HEAD^). This will hopefully allow CI to detect changes in multi-commit pushes.

Changes

I updated the check_for_changes job in ./circleci/config.yml to use git diff --name-only origin/main...HEAD.

How I tested this

I made a mulit-commit push where the first commit alters ./circleci/config.yml and the second commit is empty. The new check_for_changes command should detect the changes in ./circleci/config.yml and run the tests.

Notes

I will remove all test commits before merging into main!

Checklist

• PR has an informative and human-readable title (this will be pulled into the release notes)
• Changes are limited to a single goal (no scope creep)
• Code passed the pre-commit check & code is left cleaner/nicer than when first encountered.
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future TODOs are captured in comments
• Project documentation has been updated if adding/changing functionality.

[elijahbenizzy]

So this looks correct to me, and appears to be correct, on itself! IMO good enough for now even though there are definitely improvements we can make medium term.

[elijahbenizzy]

Looks good, I'd like to squash + rebase this so you can rebase on top of that if that's OK.