docs: fix typo in cinder docs
diff --git a/roles/cinder/README.md b/roles/cinder/README.md
index 8e8b997..2e25d1c 100644
--- a/roles/cinder/README.md
+++ b/roles/cinder/README.md
@@ -24,7 +24,7 @@
         backup_driver: cinder.backup.drivers.ceph.CephBackupDriver
 ```
 
-> **Warnings**
+> **Warning**
 >
 > It's not recommended to use same backend for volumes and backups. If you are
 > using Atmosphere's Ceph for volumes, you should use a different Ceph cluster