Properly handle soname bumps

Created by: ollieparanoid

Alpine just updated their libressl to a new soname version. Currently, pmbootstrap does not handle that, and users need to manually delete packages, that depend on libressl to build them again (e.g. weston).

After generating a package, Alpine automatically adds the .so versions a package links against to the depends, which should make it possible to handle this problem.

NOTE: Alpine handles this by bumping the pkgrel of all packages, which link against the library in question. That way, it causes a rebuild on their buildbots.