v.1.1.3 Add support for MySQL Percona XtraBackup Plugin

What's Changed

• feat(plugin): Bareos FD MySQL Percona XtraBackup Plugin by @adf-patrickha in #10

Ref: https://docs.bareos.org/TasksAndConcepts/Plugins.html#backup-mysql-xtrabackup

Full Changelog: v1.1.2...v1.1.3