pr-upload: audit only changed formulae

[dawidd6]

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew tests with your changes locally?
• Have you successfully run brew man locally and committed any changes?

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No need to read all available formulae on the machine and audit them. Only the changed ones.

[request-info]

Please provide a better issue/pull request title and/or description!