Documentation: Add gardener/etcd-backup-restore to the tools list

Etcd-backup-restore is collection of components to backup and restore the etcd. It features the periodic full and incremental backups, automated restore, Validation of etcd data directory with multi cloud provider support.

Documentation/integrations.md

@@ -19,6 +19,7 @@ title: Libraries and tools
 - [etcdloadtest](https://github.com/sinsharat/etcdloadtest) - A command line load test client for etcd version 3.0 and above.
 - [lucas](https://github.com/ringtail/lucas) - A web-based key-value viewer for kubernetes etcd3.0+ cluster.
 - [etcd-manager](https://github.com/gtamas/etcdmanager) - A modern, efficient, multi-platform and free ETCD 3.x GUI & client tool. Available for Windows, Linux and Mac.
+- [etcd-backup-restore](https://github.com/gardener/etcd-backup-restore) -  Utility to periodic and incrementally backup and restore the etcd. 
 
 **Go libraries**