Log Message:
Update py-borgbackup to 1.1.11.

Pre-1.1.11 potential index corruption / data loss issue
-------------------------------------------------------

A bug was discovered in our hashtable code, see issue #4829.
The code is used for the client-side chunks cache and the server-side repo index.

Although borg uses the hashtables very heavily, the index corruption did not
happen too frequently, because it needed specific conditions to happen.

Data loss required even more specific conditions, so it should be rare (and
also detectable via borg check).

You might be affected if borg crashed with / complained about:
- AssertionError: Corrupted segment reference count - corrupted index or hints
- ObjectNotFound: Object with key ... not found in repository ...
- Index mismatch for key b'...'. (..., ...) != (-1, -1)
- ValueError: stats_against: key contained in self but not in master_index.

Advised procedure to fix any related issue in your indexes/caches:
- install fixed borg code (on client AND server)
- for all of your clients and repos remove the cache by:
  borg delete --cache-only YOURREPO
  (later, the cache will be re-built automatically)
- for all your repos, rebuild the repo index by:
  borg check --repair YOURREPO
  This will also check all archives and detect if there is any data-loss issue.

Affected branches / releases:

fd06497 introduced the bug into 1.1-maint branch - it affects all borg 1.1.x \ 
since 1.1.0b4.
fd06497 introduced the bug into master branch - it affects all borg 1.2.0 alpha \ 
releases.
c5cd882 introduced the bug into 1.0-maint branch - it affects all borg 1.0.x \ 
since 1.0.11rc1.

The bug was fixed by:

701159a fixes the bug in 1.1-maint branch - will be released with borg 1.1.11.
fa63150 fixes the bug in master branch - will be released with borg 1.2.0a8.
7bb90b6 fixes the bug in 1.0-maint branch. Branch is EOL, no new release is \ 
planned as of now.