Explicitly define KeyCreationTime in Feb21 (#13757)

* Explicitly define KeyCreationTime

Explicitly define KeyCreationTime

* Fix KeyCreationTime Example

Fix KeyCreationTime Example

Author: hyhdtc

specification/storage/resource-manager/Microsoft.Storage/stable/2021-02-01/storage.json

@@ -2104,6 +2104,21 @@
       ],
       "description": "KeyPolicy assigned to the storage account."
     },
+    "KeyCreationTime": {
+      "properties": {
+        "key1": {
+          "type": "string",
+          "format": "date-time",
+          "example": "2021-02-03T05:57:30.917Z"
+        },
+        "key2": {
+          "type": "string",
+          "format": "date-time",
+          "example": "2021-02-03T05:57:30.917Z"
+        }
+      },
+      "description": "Storage account keys creation time."
+    },
     "EncryptionService": {
       "properties": {
         "enabled": {
@@ -2977,16 +2992,8 @@
         },
         "keyCreationTime": {
           "readOnly": true,
-          "type": "object",
-          "additionalProperties": {
-            "type": "string",
-            "format": "date-time"
-          },
-          "example": {
-            "key1": "2021-02-03T05:57:30.917Z",
-            "key2": "2021-02-03T05:55:30.917Z"
-          },
-          "description": "Gets the list of storage account keys creation time."
+          "$ref": "#/definitions/KeyCreationTime",
+          "description": "Storage account keys creation time."
         },
         "secondaryEndpoints": {
           "$ref": "#/definitions/Endpoints",