doc: mark --conditions CLI flag as stable

PR-URL: #54209
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: guybedford

doc/api/cli.md

@@ -472,12 +472,16 @@ source node_bash_completion
 added:
   - v14.9.0
   - v12.19.0
+changes:
+  - version:
+    - REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/54209
+    description: The flag is no longer experimental.
 -->
 
-> Stability: 1 - Experimental
+> Stability: 2 - Stable
 
-Enable experimental support for custom [conditional exports][] resolution
-conditions.
+Provide custom [conditional exports][] resolution conditions.
 
 Any number of custom string condition names are permitted.