Adds created at to package

doc/api/packages.md

@@ -76,7 +76,8 @@ Example response:
     "_links": {
       "web_path": "/namespace1/project1/-/packages/1",
       "delete_api_path": "/namespace1/project1/-/packages/1"
-    }
+    },
+    "created_at": "2019-11-27T03:37:38.711Z"
   },
   {
     "id": 2,
@@ -86,7 +87,8 @@ Example response:
     "_links": {
       "web_path": "/namespace1/project1/-/packages/1",
       "delete_api_path": "/namespace1/project1/-/packages/1"
-    }
+    },
+    "created_at": "2019-11-27T03:37:38.711Z"
   }
 ]
 ```
@@ -128,7 +130,8 @@ Example response:
   "_links": {
     "web_path": "/namespace1/project1/-/packages/1",
     "delete_api_path": "/namespace1/project1/-/packages/1"
-  }
+  },
+  "created_at": "2019-11-27T03:37:38.711Z"
 }
 ```
 

ee/lib/ee/api/entities.rb

@@ -870,6 +870,8 @@ module EE
             expose_url api_v4_projects_packages_path(package_id: package.id, id: package.project_id)
           end
         end
+
+        expose :created_at
       end
 
       class PackageFile < Grape::Entity

ee/spec/fixtures/api/schemas/public_api/v4/packages/package.json

@@ -26,6 +26,9 @@
           "type": "string"
         }
       }
+    },
+    "created_at": {
+      "type": "string"
     }
   }
 }