Exclude bot commits from new release notes

[Bo98]

• 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 typecheck with your changes locally?
• Have you successfully run brew tests with your changes locally?

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This will make https://github.com/Homebrew/brew/releases/tag/3.2.11 more like what we had before where dep updates were excluded.

[BrewTestBot]

Review period will end on 2021-09-09 at 11:42:49 UTC.

[MikeMcQuaid]

Thanks @Bo98, beat me to this!

[BrewTestBot]

Review period skipped due to critical label.