docs: add missing cache-copy-layers arg in README
@@ -571,6 +571,10 @@ If `--destination=gcr.io/kaniko-project/test`, then cached layers will be stored
_This flag must be used in conjunction with the `--cache=true` flag._
+#### --cache-copy-layers
+
+Set this flag to cache copy layers.
+
#### --cache-ttl duration
Cache timeout in hours. Defaults to two weeks.
