use python3-launchpadlib directly instead of python3-software-properties

debian/control

@@ -30,7 +30,7 @@ Depends: ${misc:Depends},
          procps,
          python3,
          python3-apt,
-         python3-software-properties,
+         python3-launchpadlib,
          python3-yaml,
          qemu-utils [!i386 !riscv64],
          rsync,

get-ppa-fingerprint

@@ -2,16 +2,14 @@
 
 from __future__ import print_function
 
+from launchpadlib.launchpad import Launchpad
 from optparse import OptionParser
 
-from softwareproperties import ppa
-
 
 parser = OptionParser(usage="%prog OWNER/NAME")
 _, args = parser.parse_args()
 if not args:
     parser.error("must provide a PPA owner/name")
 owner_name, ppa_name = args[0].split("/", 1)
-owner_name = "~%s" % owner_name
-ppa_info = ppa.get_ppa_info_from_lp(owner_name, ppa_name)
-print(ppa_info["signing_key_fingerprint"])
+lp = Launchpad.login_anonymously('livecd-rootfs')
+print(lp.people(owner_name).getPPAByName(name=ppa_name).signing_key_fingerprint)