Add /sys/devices/virtual/powercap to Masked Paths in security-context.md

The document does not reflect the following: ref kubernetes/kubernetes#125970

Author: yosshi825

content/en/docs/tasks/configure-pod-container/security-context.md

@@ -498,6 +498,7 @@ them. The list of masked and read-only paths are as follows:
  - `/proc/sched_debug`
  - `/proc/scsi`
  - `/sys/firmware`
+ - `/sys/devices/virtual/powercap`
 
 - Read-Only Paths:
  - `/proc/bus`
@@ -578,4 +579,4 @@ kubectl delete pod security-context-demo-4
 * Read about [User Namespaces](/docs/concepts/workloads/pods/user-namespaces/)
  for Linux pods.
 * [Masked Paths in the OCI Runtime
- Specification](https://github.com/opencontainers/runtime-spec/blob/f66aad47309/config-linux.md#masked-paths)
+ Specification](https://github.com/opencontainers/runtime-spec/blob/f66aad47309/config-linux.md#masked-paths)