borgmatic 1.5.11

• #341: Add "temporary_directory" option for changing Borg's temporary directory.
• #352: Lock down systemd security settings in sample systemd service file.
• #355: Fix traceback when a database hook value is null in a configuration file.
• #361: Merge override values when specifying the "--override" flag multiple times. The previous
  behavior was to take the value of the last "--override" flag only.
• #367: Fix traceback when upgrading old INI-style configuration with upgrade-borgmatic-config.
• #368: Fix signal forwarding from borgmatic to Borg resulting in recursion traceback.
• #369: Document support for Borg placeholders in repository names.