Update v8 implementation status

Author: sbc100

proposals/extended-const/Overview.md

@@ -50,7 +50,7 @@ instruction:
 - spec interpreter: Done
 - wabt: [Done](https://github.com/WebAssembly/debugging/issues/17#issuecomment-1041130743)
 - Firefox: [Done](https://github.com/WebAssembly/debugging/issues/17#issuecomment-1041130743)
-- v8: [WIP](https://bugs.chromium.org/p/v8/issues/detail?id=12089)
+- v8: [Done](https://chromium.googlesource.com/v8/v8/+/bf1565d7081cabc510e39c42eaea67ea6e79484e)
 
 [spec]: https://webassembly.github.io/spec/core/valid/instructions.html#constant-expressions
 [presentation]: https://docs.google.com/presentation/d/1sM9mJJ6iM7D8324ipYxot91hSKnWCtB8jX4Kh3bde5E