add version field at the schema top level

Author: andrii-i

json-schema/workflow.schema.json renamed to src/schema/workflow.schema.json

@@ -1,9 +1,12 @@
 {
   "$schema": "http://json-schema.org/draft-07/schema#",
-  "version": "0.0.1",
   "title": "Workflow",
   "type": "object",
   "properties": {
+    "schemaVersion": {
+      "type": "string",
+      "default": "0.0.1"
+    },
     "tasks": {
       "type": "array",
       "items": {
@@ -31,7 +34,10 @@
       "description": "Timezone for the schedule."
     }
   },
-  "required": ["tasks", "name"],
+  "required": [
+    "tasks",
+    "name"
+  ],
   "definitions": {
     "Task": {
       "type": "object",
@@ -95,7 +101,11 @@
           "description": "DAG node ID of this task."
         }
       },
-      "required": ["input_uri", "name", "node_id"]
+      "required": [
+        "input_uri",
+        "name",
+        "node_id"
+      ]
     }
   }
-}
+}