Add provides method
Currently, the database methods let you find a package by name:
>>> db.get_pkg('bash')
<alpm.Package("bash-5.0.011-2-x86_64") at 0x7f0c9b5fb5b0>
However, providers or virtual packages do not return anything:
>>> db.get_pkg('sh')
>>> # should also return bash
A method such as provides
would be desirable, such that you could find the package that's providing a dependency in your system.