doc: add missing changes entry

The `util.format()` behavior changed recently. Add the changes entry
to document the new BigInt behavior.

PR-URL: #24758
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

Author: BridgeAR

doc/api/util.md

@@ -183,6 +183,9 @@ property take precedence over `--trace-deprecation` and
 <!-- YAML
 added: v0.5.3
 changes:
+  - version: v10.12.0
+    pr-url: https://github.com/nodejs/node/pull/22097
+    description: The `%d` and `%i` specifiers now support BigInt.
   - version: v8.4.0
     pr-url: https://github.com/nodejs/node/pull/14558
     description: The `%o` and `%O` specifiers are supported now.