run feature-request action on labeled action (#980)

Run the feature request management action when adding "feature" label.

This will allow us to..
1. remove "feature" label
2. add back "feature" label

Thus execute the workflow on the existing issues.

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

@@ -2,7 +2,7 @@ name: Close feature requests with automated message
 
 on:
   issues:
-    types: [opened]
+    types: [labeled]
 
 jobs:
   needs-votes:

upcoming-release-notes/980.md

+---
+category: Maintenance
+authors: [MatissJanis]
+---
+
+Run feature-request management github action when the "feature" label is added