passlib has not be updated since 2020 and is therefore a dead project.
Radicale (used in this repo as radicale3) has updated to use libpass (a
maintained fork of passlib): https://github.com/Kozea/Radicale/pull/1953
therefore add python3-libpass to provide libpass, a drop-in replacement
for passlib, and a dependency for Radicale v3.6.0.
Signed-off-by: Daniel F. Dickinson <dfdpublic@wildtechgarden.ca>
