Update the pkgdb2 rpm to 1.20.1-2

In this release, backport the changes from https://github.com/fedora-infra/pkgdb2/pull/109
fixing the API to orphan someone's packages
Fix api_package_orphan: former_poc is not a list but a single element
Fix missed docstrings indentation
Fix patch and build a 1.20.1-3 bug fix release