doc: add history entry for exports patterns

PR-URL: https://github.com/nodejs/node/pull/35410
Refs: https://github.com/nodejs/node/pull/34718
Reviewed-By: Rich Trott <rtrott@gmail.com>

doc/api/packages.md

@@ -896,6 +896,10 @@ changes:
     - v13.7.0
     pr-url: https://github.com/nodejs/node/pull/31008
     description: Implement logical conditional exports ordering.
+  - version:
+    - v14.13.0
+    pr-url: https://github.com/nodejs/node/pull/34718
+    description: Add support for `"exports"` patterns.
 -->
 
 * Type: {Object} | {string} | {string[]}