Fix a JSON schema validation issue for group milestone

Signed-off-by: Rémy Coutable <remy@rymai.me>

spec/fixtures/api/schemas/public_api/v4/ee/issues.json

 {
-  "type": "array",
-  "items": {
-    "type": "object",
-    "properties" : {
-      "id": { "type": "integer" },
-      "iid": { "type": "integer" },
-      "project_id": { "type": "integer" },
-      "title": { "type": "string" },
-      "description": { "type": ["string", "null"] },
-      "state": { "type": "string" },
-      "created_at": { "type": "date" },
-      "updated_at": { "type": "date" },
-      "labels": {
-        "type": "array",
-        "items": {
-          "type": "string"
-        }
-      },
-      "milestone": {
-        "type": "object",
-        "properties": {
-          "id": { "type": "integer" },
-          "iid": { "type": "integer" },
-          "project_id": { "type": "integer" },
-          "group_id": { "type": ["integer", "null"] },
-          "title": { "type": "string" },
-          "description": { "type": ["string", "null"] },
-          "state": { "type": "string" },
-          "created_at": { "type": "date" },
-          "updated_at": { "type": "date" },
-          "due_date": { "type": "date" },
-          "start_date": { "type": "date" }
-        },
-        "additionalProperties": false
-      },
-      "assignees": {
-        "type": "array",
-        "items": {
-          "type": ["object", "null"],
-          "properties": {
-            "name": { "type": "string" },
-            "username": { "type": "string" },
-            "id": { "type": "integer" },
-            "state": { "type": "string" },
-            "avatar_url": { "type": "uri" },
-            "web_url": { "type": "uri" }
-          },
-          "additionalProperties": false
-        }
-      },
-      "assignee": {
-        "type": ["object", "null"],
-        "properties": {
-          "name": { "type": "string" },
-          "username": { "type": "string" },
-          "id": { "type": "integer" },
-          "state": { "type": "string" },
-          "avatar_url": { "type": "uri" },
-          "web_url": { "type": "uri" }
-        },
-        "additionalProperties": false
-      },
-      "author": {
-        "type": "object",
+  "allOf": [
+    { "$ref": "../issues.json" },
+    {
       "properties": {
-          "name": { "type": "string" },
-          "username": { "type": "string" },
-          "id": { "type": "integer" },
-          "state": { "type": "string" },
-          "avatar_url": { "type": "uri" },
-          "web_url": { "type": "uri" }
-        },
-        "additionalProperties": false
-      },
-      "user_notes_count": { "type": "integer" },
-      "upvotes": { "type": "integer" },
-      "downvotes": { "type": "integer" },
-      "due_date": { "type": ["date", "null"] },
-      "confidential": { "type": "boolean" },
-      "web_url": { "type": "uri" },
         "weight": { "type": ["integer", "null"] }
-    },
-    "required": [
-      "id", "iid", "project_id", "title", "description",
-      "state", "created_at", "updated_at", "labels",
-      "milestone", "assignees", "author", "user_notes_count",
-      "upvotes", "downvotes", "due_date", "confidential",
-      "web_url", "weight"
-    ],
-    "additionalProperties": false
       }
+    }
+  ]
 }

spec/fixtures/api/schemas/public_api/v4/issues.json

@@ -86,7 +86,6 @@
       "milestone", "assignees", "author", "user_notes_count",
       "upvotes", "downvotes", "due_date", "confidential",
       "web_url"
-    ],
-    "additionalProperties": false
+    ]
   }
 }

spec/support/api/milestones_shared_examples.rb

@@ -229,7 +229,7 @@ shared_examples_for 'group and project milestones' do |route_definition|
       get api(issues_route, user)
 
       expect(response).to have_http_status(200)
-      expect(response).to match_response_schema('public_api/v4/issues')
+      expect(response).to match_response_schema('public_api/v4/ee/issues')
     end
 
     it 'returns a 401 error if user not authenticated' do