Show package information dependent on tag/branch (like Packagist does)

[jaylinski]

Is your feature request related to a problem? Please describe.
We use the Satis "Required by"-info to check if old packages are unused and can be safely deleted/abandoned.
Since Satis uses all repo tags and branches in order to determine the "Required by"-information, the "Required by" list just grows longer and longer (because we don't delete old releases/tags that still contain packages that have been removed in newer tags/releases).

So even if a package is already unused in the current release of our packages, it still shows up in "Required by" because it is used in older releases. This makes the "Required by"-info useless for us, because we are only interested in the "Required by"-info for a specific (in our case the latest) tag/branch.

Describe the solution you'd like
Show the package information based on tags/branches, similar to what packagist.org does with the tag-selection:

Describe alternatives you've considered
The alternative is to delete old branches/tags, so that Satis will not pick up information from "composer.json"-files in old/unused tags/branches.

This approach is cumbersome, since one always has to remember to delete old tags.

Additional context

I can create a PR if you (package maintainers) consider this a useful feature.