Remove BackupPC

Dead Project. Last Release 2020.

https://github.com/backuppc/backuppc/issues/481

README.md

@@ -88,7 +88,6 @@ _See also: [Restic's list of Linux backup software](https://github.com/restic/ot
 
 - [Amanda](https://www.amanda.org/) - Backup and archive many computers on a network to disk, tape changer/drive or cloud storage. ([Source Code](https://github.com/zmanda/amanda)) `MIT` `C`
 - [Backupninja](https://0xacab.org/liberate/backupninja) - Lightweight, extensible meta-backup system, provides a centralized way to configure and coordinate many different backup utilities. `GPL-2.0` `Shell`
-- [BackupPC](https://backuppc.github.io/backuppc/) - High-performance, enterprise-grade system for backing up to a server's disk.. ([Source Code](https://github.com/backuppc/backuppc)) `GPL-3.0` `Perl`
 - [Bareos](https://www.bareos.org/) - Cross-network backup solution which preserves, archives, and recovers data from all major operating systems. ([Source Code](https://github.com/bareos/bareos)) `AGPL-3.0` `C++/C`
 - [Barman](https://pgbarman.org) - Backup and Recovery Manager for PostgreSQL. ([Source Code](https://github.com/EnterpriseDB/barman)) `GPL-3.0` `Python`
 - [BorgBackup](https://www.borgbackup.org/) - Deduplicating archiver with compression and authenticated encryption. ([Source Code](https://github.com/borgbackup/borg)) `BSD-3-Clause` `Python`