Skip autofix on PRs in pre-commit

[ciarams87]

Proposed changes

Problem: The pre-commit check running in PRs is auto-fixing issues it finds. While that is desirable behaviour when we run pre-commit locally, it is not something we want in PRs because it alters the remote branch which can affect the developer workflow.

Solution: The pre-commit docs details a configuration option to disable this autofix feature. The solution is to add this field to the config.

Closes #898

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[kate-osborn]

👍

[lucacome]

autofix was left on to help with minor fixes like whitespaces, especially for external people without forcing them to install pre-commit 🤔

[ciarams87]

autofix was left on to help with minor fixes like whitespaces, especially for external people without forcing them to install pre-commit 🤔

@lucacome The team were discussing this offline yesterday, and having external contributors on dev branches (even if only the pre-commit bot) interrupts dev workflows - personally, I was caught out by it because my remote branch changed unexpectedly so I needed to rebase locally. External contributors don't need to necessarily install pre-commit, they can make the changes manually as detailed in the pre-commit report in the PR. If in the future it is causing issues for external contributors, we can always look at re-instating this functionality.