Update AlertRules.json (Azure#18640)

Author: Amitbergman

specification/securityinsights/resource-manager/Microsoft.SecurityInsights/stable/2020-01-01/AlertRules.json

@@ -950,6 +950,12 @@
           "description": "The display name for alert rule template.",
           "type": "string"
         },
+        "lastUpdatedDateUTC": {
+          "description": "The time that this alert rule template was last updated.",
+          "format": "date-time",
+          "readOnly": true,
+          "type": "string"
+        },
         "requiredDataConnectors": {
           "description": "The required data connectors for this template",
           "items": {
@@ -1112,6 +1118,12 @@
           "description": "The display name for alert rule template.",
           "type": "string"
         },
+        "lastUpdatedDateUTC": {
+          "description": "The time that this alert rule template was last updated.",
+          "format": "date-time",
+          "readOnly": true,
+          "type": "string"
+        },
         "requiredDataConnectors": {
           "description": "The required data connectors for this template",
           "items": {
@@ -1303,6 +1315,12 @@
           "description": "The display name for alert rule template.",
           "type": "string"
         },
+        "lastUpdatedDateUTC": {
+          "description": "The time that this alert rule template was last updated.",
+          "format": "date-time",
+          "readOnly": true,
+          "type": "string"
+        },
         "requiredDataConnectors": {
           "description": "The required data connectors for this template",
           "items": {