build: allow manual run of feature request action

add "workflow_dispatch:" so that action can be run
manuallyl for debugging.

Signed-off-by: Michael Dawson <mdawson@devrus.com>

PR-URL: https://github.com/nodejs/node/pull/42037
Reviewed-By: Mestery <mestery@protonmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>

.github/workflows/close-stale-feature-requests.yml

@@ -1,5 +1,6 @@
 name: Close stale feature requests
 on:
+  workflow_dispatch:
   schedule:
     # Run every day at 1:00 AM UTC.
     - cron: 0 1 * * *