kiosk: Add kiosk.always_update manifest key

extensions/common/api/_manifest_features.json

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This features file defines manifest keys implemented under src/extensions.
 // See chrome/common/extensions/api/_features.md to understand this file, as
 // well as feature.h, simple_feature.h, and base_feature_provider.h.
 
 {
   "app": {
@@ skipping 155 matching lines @@
     }
   ],
   "key": {
     "channel": "stable",
     "extension_types": "all"
   },
   "kiosk": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   },
+  "kiosk.always_update": {
+    "channel": "stable",
+    "extension_types": ["platform_app"]
+  },
   "kiosk.required_platform_version": {
     "channel": "stable",
     "extension_types": ["platform_app"]
   },
   "kiosk_enabled": {
     "channel": "stable",
     "extension_types": [
       "platform_app"
     ]
   },
@@ skipping 136 matching lines @@
       "extension_types": ["platform_app"],
       "location": "component"
     }
   ],
   "webview": {
     "channel": "stable",
     "extension_types": ["platform_app"],
     "min_manifest_version": 2
   }
 }