archivers/py-borgbackup: update to 1.2.2+man+test, preserve 1.1

Take maintainership, because original maintainer asked for a new
maintainer, https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=264816#c10

¡Muchas gracias, José! Thanks for maintaining the port thus far.

If there is a potential maintainer who is using BorgBackup at scale,
I will be happy to pass maintainership on.

Update to v1.2.2 [1, was for 1.2.1],
preserve the earlier 1.1.18 version (also with manpages and self-tests added,
hence bumping PORTREVISION) as py-borgbackup11, and document this in UPDATING.

ChangeLog: https://www.borgbackup.org/releases/borg-1.2.html

Add self-tests [1] to both 1.1 and 1.2, including
- a smoke test in post-install in order to always run it
- "make test" support (requires network access for tox)

PR:		264816 [1]
Reported by:	rob2g2-freebsd@bitbert.com [1]

Add manual pages to both 1.1 and 1.2. [2]

PR:		263269 [2]
Reported by:	courtney.hicks1@icloud.com [2]