add bulk deletion support to ark backup delete

Signed-off-by: Steve Kriss <steve@heptio.com>

docs/cli-reference/ark_backup.md

@@ -31,7 +31,7 @@ Work with backups
 ### SEE ALSO
 * [ark](ark.md)	 - Back up and restore Kubernetes cluster resources.
 * [ark backup create](ark_backup_create.md)	 - Create a backup
-* [ark backup delete](ark_backup_delete.md)	 - Delete a backup
+* [ark backup delete](ark_backup_delete.md)	 - Delete backups
 * [ark backup describe](ark_backup_describe.md)	 - Describe backups
 * [ark backup download](ark_backup_download.md)	 - Download a backup
 * [ark backup get](ark_backup_get.md)	 - Get backups

docs/cli-reference/ark_backup_delete.md

@@ -1,21 +1,43 @@
 ## ark backup delete
 
-Delete a backup
+Delete backups
 
 ### Synopsis
 
 
-Delete a backup
+Delete backups
 
 ```
-ark backup delete NAME [flags]
+ark backup delete [NAMES] [flags]
+```
+
+### Examples
+
+```
+  # delete a backup named "backup-1"
+  ark backup delete backup-1
+
+  # delete a backup named "backup-1" without prompting for confirmation
+  ark backup delete backup-1 --confirm
+
+  # delete backups named "backup-1" and "backup-2"
+  ark backup delete backup-1 backup-2
+
+  # delete all backups triggered by schedule "schedule-1"
+  ark backup delete --selector ark-schedule=schedule-1
+ 
+  # delete all backups
+  ark backup delete --all
+  
 ```
 
 ### Options
 
 ```
-      --confirm   Confirm deletion
-  -h, --help      help for delete
+      --all                      Delete all backups
+      --confirm                  Confirm deletion
+  -h, --help                     help for delete
+  -l, --selector labelSelector   Delete all backups matching this label selector (default <none>)
 ```
 
 ### Options inherited from parent commands

docs/cli-reference/ark_delete.md

@@ -30,7 +30,7 @@ Delete ark resources
 
 ### SEE ALSO
 * [ark](ark.md)	 - Back up and restore Kubernetes cluster resources.
-* [ark delete backup](ark_delete_backup.md)	 - Delete a backup
+* [ark delete backup](ark_delete_backup.md)	 - Delete backups
 * [ark delete restore](ark_delete_restore.md)	 - Delete a restore
 * [ark delete schedule](ark_delete_schedule.md)	 - Delete a schedule
 

docs/cli-reference/ark_delete_backup.md

@@ -1,21 +1,43 @@
 ## ark delete backup
 
-Delete a backup
+Delete backups
 
 ### Synopsis
 
 
-Delete a backup
+Delete backups
 
 ```
-ark delete backup NAME [flags]
+ark delete backup [NAMES] [flags]
+```
+
+### Examples
+
+```
+  # delete a backup named "backup-1"
+  ark backup delete backup-1
+
+  # delete a backup named "backup-1" without prompting for confirmation
+  ark backup delete backup-1 --confirm
+
+  # delete backups named "backup-1" and "backup-2"
+  ark backup delete backup-1 backup-2
+
+  # delete all backups triggered by schedule "schedule-1"
+  ark backup delete --selector ark-schedule=schedule-1
+ 
+  # delete all backups
+  ark backup delete --all
+  
 ```
 
 ### Options
 
 ```
-      --confirm   Confirm deletion
-  -h, --help      help for backup
+      --all                      Delete all backups
+      --confirm                  Confirm deletion
+  -h, --help                     help for backup
+  -l, --selector labelSelector   Delete all backups matching this label selector (default <none>)
 ```
 
 ### Options inherited from parent commands