[ja] Add runAsGroup and change appropriate image

content/ja/examples/pods/security/security-context-3.yaml

@@ -6,6 +6,3 @@ spec:
   containers:
   - name: sec-ctx-3
     image: gcr.io/google-samples/node-hello:1.0
-
-
-

content/ja/examples/pods/security/security-context.yaml

@@ -5,13 +5,15 @@ metadata:
 spec:
   securityContext:
     runAsUser: 1000
+    runAsGroup: 3000
     fsGroup: 2000
   volumes:
   - name: sec-ctx-vol
     emptyDir: {}
   containers:
   - name: sec-ctx-demo
-    image: gcr.io/google-samples/node-hello:1.0
+    image: busybox:1.28
+    command: [ "sh", "-c", "sleep 1h" ]
     volumeMounts:
     - name: sec-ctx-vol
       mountPath: /data/demo