borgmatic 1.5.7

• #327: Fix broken pass-through of BORG_* environment variables to Borg.
• #328: Fix duplicate logging to Healthchecks and send "after_*" hooks output to Healthchecks.
• #331: Add SSL support to PostgreSQL database configuration.
• #333: Fix for potential data loss (data not getting backed up) when borgmatic omitted configured
  source directories in certain situations. Specifically, this occurred when two source directories
  on different filesystems were related by parentage (e.g. "/foo" and "/foo/bar/baz") and the
  one_file_system option was enabled.
• Update documentation code fragments theme to better match the rest of the page.
• Improve configuration reference documentation readability via more aggressive word-wrapping in
  configuration schema descriptions.