databases/xtrabackup80: Remove incorrectly added deprecation/expiration
This was incorrectly marked as deprecated. It is in fact supported and
under active development by Percona.
See PXB 8.0.x under the MySQL Software table of:
https://www.percona.com/services/policies/percona-software-support-lifecycle
databases/xtrabackup80 is required for MySQL 8.0.x and
databases/xtrabackup84 is required for MySQL 8.4.x