Added "$schema" as property (#734)

Author: o-l-a-v

Schemas/global-settings-schema.json

@@ -2,6 +2,10 @@
     "$schema": "https://json-schema.org/draft/2020-12/schema",
     "type": "object",
     "properties": {
+        "$schema": {
+            "type": "string",
+            "description": "The schema to verify this document against."
+        },
         "pacOwnerId": {
             "type": "string"
         },
@@ -136,4 +140,4 @@
         "pacOwnerId",
         "pacEnvironments"
     ]
-}
+}