Update SIMD-0166 with feature key (#314)

proposals/0166-dynamic-stack-frames.md

@@ -9,7 +9,7 @@ category: Standard
 type: Core
 status: Implemented
 created: 2024-08-19T00:00:00.000Z
-feature: null
+feature: JE86WkYvTrzW8HgNmrHY7dFYpCmSptUpKupbo2AdQ9cG
 supersedes: null
 superseded-by: null
 extends: null