Update rest-api-spec (#4553)

Co-authored-by: pquentin <[email protected]>

Author: github-actions[bot]

output/schema/schema.json

@@ -7,7 +7,7 @@
     "stability": "experimental",
     "visibility": "public",
     "headers": {
-      "accept": [],
+      "accept": ["application/json"],
       "content_type": ["application/json"]
     },
     "url": {