Consider inlining pre-commit update actions

[colindean]

We use https://github.com/browniebroke/pre-commit-autoupdate-action in the pre-commit updater workflow, but it's actually really simple. Even the author of it seems to have moved on, creating and using their own version that inlines the action in https://github.com/browniebroke/github-actions/blob/main/.github/workflows/pre-commit-autoupdate.yml.

[colindean]

This would eliminate the need for browniebroke/pre-commit-autoupdate-action#4 and browniebroke/pre-commit-autoupdate-action#5.