doc: mention CryptoKey in port.postMessage()

PR-URL: #37196
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

doc/api/worker_threads.md

@@ -477,6 +477,9 @@ changes:
   - version: v15.6.0
     pr-url: https://github.com/nodejs/node/pull/36804
     description: Added `X509Certificate` to the list of cloneable types.
+  - version: v15.0.0
+    pr-url: https://github.com/nodejs/node/pull/35093
+    description: Added `CryptoKey` to the list of cloneable types.
   - version:
     - v14.5.0
     - v12.19.0
@@ -505,7 +508,7 @@ In particular, the significant differences to `JSON` are:
    and `SharedArrayBuffer`s.
 * `value` may contain [`WebAssembly.Module`][] instances.
 * `value` may not contain native (C++-backed) objects other than {MessagePort}s,
-  {FileHandle}s, {KeyObject}s, and {X509Certificate}s.
+  {FileHandle}s, {KeyObject}s, {CryptoKey}s, and {X509Certificate}s.
 
 ```js
 const { MessageChannel } = require('worker_threads');