Add generic type to remote derive example

docs/_includes/examples/remote_derive.schema.json

@@ -4,12 +4,19 @@
   "type": "object",
   "required": [
     "command_line",
+    "durations",
     "wall_time"
   ],
   "properties": {
     "command_line": {
       "type": "string"
     },
+    "durations": {
+      "type": "array",
+      "items": {
+        "$ref": "#/definitions/Duration"
+      }
+    },
     "wall_time": {
       "$ref": "#/definitions/Duration"
     }