During merge, I forgot to drop -dev suffix.

Change-Id: I50399ae9fa34d090936216ee3abbff130eaa4efd
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/402354
Run-TryBot: Hyang-Ah Hana Kim <[email protected]>
Reviewed-by: Nooras Saba‎ <[email protected]>
TryBot-Result: kokoro <[email protected]>