Add fibersapi feature to winapi in rustc-workspace-hack

Co-authored-by: Eric Huss <ehuss@users.noreply.github.com>

Author: flip1995

src/tools/rustc-workspace-hack/Cargo.toml

@@ -22,6 +22,7 @@ features = [
   "basetsd",
   "consoleapi",
   "errhandlingapi",
+  "fibersapi",
   "ioapiset",
   "jobapi",
   "jobapi2",