doc(rdb): udpate volume-type sbs_15k (scaleway#2555)

Author: jremy42

docs/resources/rdb_instance.md

@@ -127,7 +127,7 @@ and if you are using `bssd` storage, you should increase the volume size before
 
 ~> **Important:** Updates to `engine` will recreate the Database Instance.
 
-- `volume_type` - (Optional, default to `lssd`) Type of volume where data are stored (`bssd`, `lssd` or `sbs_5k`).
+- `volume_type` - (Optional, default to `lssd`) Type of volume where data are stored (`bssd`, `lssd`, `sbs_5k` or `sbs_15k`).
 
 - `volume_size_in_gb` - (Optional) Volume size (in GB). Cannot be used when `volume_type` is set to `lssd`.
 

internal/services/rdb/instance.go

@@ -135,6 +135,7 @@ func ResourceInstance() *schema.Resource {
 					rdb.VolumeTypeLssd.String(),
 					rdb.VolumeTypeBssd.String(),
 					rdb.VolumeTypeSbs5k.String(),
+					rdb.VolumeTypeSbs15k.String(),
 				}, false),
 				Description: "Type of volume where data are stored",
 			},