Allow auto-accepting "trivial" PKGBUILD changes

[HadrienG2]

Have you checked the readme and man page for this feature? Yes. Have you checked previous issues for this feature? Yes.

Since AUR recipes are not externally reviewed, the default paru configuration asks users to review full build recipes on first package installation, and recipe diffs on every update. This is, generally speaking, an important security feature, as it offers a basic protection against rogue/hacked AUR package maintainers injecting malicious code into an initially good package build recipe.

However, in practice, most AUR package changes contain nothing but a version number bump and git commit hash or tarball digest change. In this case, the PKGBUILD diff contains no new information compared to a summary listing of upstream version number change for all updated packages (as shown by pacman -Syu), which would be enough to prompt interested user to review the upstream changelog/diff.

Needing to frequently review and interactively accept such inconsequential PKGBUILD changes on a per-package basis ultimately leads to notification fatigue, and thus a tendency for paru users to say "yes" without reading the diff carefully. Which defeats the purpose of this feature.

It would therefore be nice if there existed a middle ground between the two --review and --skipreview configurations currently provided by paru, where an automated analysis (which might be user-controlled) could be run on the PKGBUILD diff at the beginning of the review process, to determines if it is a trivial change by the above definition. If this automated analysis passes (indicating a trivial diff), the user will not be asked to review the diff. If it fails (indicating a non-trivial diff), then paru will proceed with manual review as it does today.