chore: fix label used in feature request template (#2761)

Author: lumtis

.github/ISSUE_TEMPLATE/feature_request.md

@@ -2,7 +2,7 @@
 name: Feature Request
 about: Suggest an idea for this project
 title: ''
-labels: 'feature'
+labels: 'feature:idea'
 assignees: ''
 
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