doc: fix conditional exports flag removal version

Backport-PR-URL: #35757
PR-URL: #35428
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Myles Borins <myles.borins@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/packages.md

@@ -853,7 +853,7 @@ changes:
     pr-url: https://github.com/nodejs/node/pull/29978
     description: Implement conditional exports.
   - version:
-    - v12.15.0
+    - v12.16.0
     pr-url: https://github.com/nodejs/node/pull/31001
     description: Remove the `--experimental-conditional-exports` option.
   - version: