libpod.conf: clarify `label` description
Clarify that the label option sets the defaults which can still be
overriden by the CLI.
@@ -83,7 +83,8 @@ libpod to manage containers.
containers and pods are visible.
**label**="true|false"
- Indicates whether the containers should use label separation.
+ Indicates whether the containers should use label separation by default.
+ Can be overridden via `--security-opt label=...` on the CLI.
**num_locks**=""
Number of locks available for containers and pods. Each created container or pod consumes one lock.
