software/erp5: use allOf to extend caucase schema

software/erp5/instance-erp5-input-schema.json

@@ -498,6 +498,8 @@
     },
     "caucase": {
       "description": "Caucase certificate authority parameters",
+      "allOf": [
+        {
           "properties": {
             "url": {
               "title": "Caucase URL",
@@ -506,10 +508,12 @@
               "type": "string",
               "format": "uri"
             }
+          }
         },
-      "additionalProperties": {
+        {
           "$ref": "../caucase/instance-caucase-input-schema.json"
-      },
+        }
+      ],
       "type": "object"
     },
     "test-runner": {