fix: add missing nix dep

cli/flake.nix

···
             } // pkgs.lib.optionalAttrs (target == "x86_64-pc-windows-gnu") {
               depsBuildBuild = with pkgs; [
                 pkgsCross.mingwW64.stdenv.cc
+                pkgsCross.mingwW64.windows.pthreads
+              ];
+              nativeBuildInputs = commonArgs.nativeBuildInputs ++ [
+                pkgs.pkgsCross.mingwW64.windows.pthreads
               ];
               CARGO_TARGET_X86_64_PC_WINDOWS_GNU_LINKER = "${pkgs.pkgsCross.mingwW64.stdenv.cc}/bin/x86_64-w64-mingw32-gcc";
             })