Add custom config fields

Author: BNAndras

exercises/practice/relative-distance/.meta/config.json

@@ -15,5 +15,11 @@
   },
   "blurb": "Given a family tree, calculate the degree of separation.",
   "source": "vaeng",
-  "source_url": "https://github.com/exercism/problem-specifications/pull/2537"
+  "source_url": "https://github.com/exercism/problem-specifications/pull/2537",
+  "custom": {
+    "version.tests.compatibility": "jest-27",
+    "flag.tests.task-per-describe": false,
+    "flag.tests.may-run-long": false,
+    "flag.tests.includes-optional": false
+  }
 }