Add support for Piers.

[ksooo]

No description provided.

[ksooo]

Hmm, are the tests failing because we do not have a Piers addon-repo? Just guessing...

self = <kodi_addon_checker.addons.Repository.Repository object at 0x7fa5baa7d850>
addonId = 'script.test'

    def __contains__(self, addonId):
>       for addon in self.addons:
E       AttributeError: 'Repository' object has no attribute 'addons'

kodi_addon_checker/addons/Repository.py:78: AttributeError
=========================== short test summary info ============================
FAILED tests/test_check_addon.py::TestCheckAddon::test_start - AttributeError: 'Repository' object has no attribute 'addons'

[ksooo]

Hmm, are the tests failing because we do not have a Piers addon-repo? Just guessing...

Meanwhile the piers repo is online at the mirrors: https://mirrors.kodi.tv/addons/piers/