add caution

resource/locales/en_US/translation.json

@@ -551,6 +551,7 @@
     "session": "Session",
     "max_age": "Max age (msec)",
     "max_age_desc": "Specifies the number (in milliseconds) to expire users session.<br>Default: 2592000000 (30days)",
+    "max_age_caution": "Restarting the server is required after you modify this value.",
     "Authentication mechanism settings": "Authentication Mechanism Settings",
     "setup_is_not_yet_complete": "Setup is not yet complete",
     "alert_siteUrl_is_not_set": "'Site URL' is NOT set. Set it from the {{link}}",

resource/locales/ja_JP/translation.json

@@ -553,6 +553,7 @@
     "session": "セッション",
     "max_age": "有効期間 (ミリ秒)",
     "max_age_desc": "ユーザーのセッション情報の有効期間をミリ秒で指定できます。<br>デフォルト値: 2592000000 (30日間)",
+    "max_age_caution": "この値を変更した後は、サーバーを再起動する必要があります。",
     "Authentication mechanism settings": "認証機構設定",
     "setup_is_not_yet_complete":"セットアップはまだ完了してません",
     "alert_siteUrl_is_not_set": "'サイトURL' が設定されていません。{{link}} から設定してください。",

resource/locales/zh_CN/translation.json

@@ -539,6 +539,7 @@
     "session": "会议",
     "max_age": "有效期间  (msec)",
     "max_age_desc": "指定使用户会话过期的数量(以毫秒为单位)。<br>默认值: 2592000000 (30天)",
+    "max_age_caution": "修改该值后需要重启服务器。",
 		"Authentication mechanism settings": "身份验证机制设置",
 		"setup_is_not_yet_complete": "安装尚未完成",
 		"alert_siteUrl_is_not_set": "主页URL未设置，通过 {{link}} 设置",

src/client/js/components/Admin/Security/SecuritySetting.jsx

@@ -59,6 +59,11 @@ class SecuritySetting extends React.Component {
             />
             {/* eslint-disable-next-line react/no-danger */}
             <p className="form-text text-muted" dangerouslySetInnerHTML={{ __html: t('security_setting.max_age_desc') }} />
+            <p className="card well">
+              <span className="text-warning">
+                <i className="icon-info"></i> {t('security_setting.max_age_caution')}
+              </span>
+            </p>
           </div>
         </div>