Borgmatic

* 46: Declare dependency on pykwalify 1.6 or above, as older versions yield "Unknown key: version"
rule errors.
* Support for Borg --keep-minutely prune option.

* 26: Add "ssh_command" to configuration for specifying a custom SSH command or options.
* Fix for incorrect /etc/borgmatic.d/ configuration path probing on macOS. This problem manifested
as an error on startup: "[Errno 2] No such file or directory: '/etc/borgmatic.d'".

* Pass several Unix signals through to child processes like Borg. This means that Borg now properly
shuts down if borgmatic is terminated (e.g. due to a system suspend).
* 30: Support for using tilde in repository paths to reference home directory.
* 43: Support for Borg --files-cache option for setting the files cache operation mode.
* 45: Support for Borg --remote-ratelimit option for limiting upload rate.
* Log invoked Borg commands when at highest verbosity level.

* 17, 39: Support for user-defined hooks before/after backup, or on error.
* 34: Improve clarity of logging spew at high verbosity levels.
* 30: Support for using tilde in source directory path to reference home directory.
* Require "prefix" in retention section when "archive_name_format" is set. This is to avoid
accidental pruning of archives with a different archive name format. For similar reasons, default
"prefix" to "{hostname}-" if not specified.
* Convert main source repository from Mercurial to Git.
* Update dead links to Borg documentation.

* 40: Fix to make /etc/borgmatic/config.yaml optional rather than required when using the default
config paths.

* 29: Add "archive_name_format" to configuration for customizing archive names.
* Fix for traceback when "exclude_from" value is empty in configuration file.
* When pruning, make highest verbosity level list archives kept and pruned.
* Clarification of Python 3 pip usage in documentation.