bump-formula-pr: autobump livecheck-defined resources

[cho-m]

This expands prior logic for :parent resources to also allow autobumping livecheck-defined resources.

Only works for some standard formats so can't deal with on_system blocks within resources, comments, etc. yet.

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[MikeMcQuaid]

Looks good when 🟢 and @samford is 👍🏻