bws: build with `--package`

pkgs/tools/security/bws/default.nix

···
     RUSTONIG_SYSTEM_LIBONIG = true;
   };
 
-  buildAndTestSubdir = "crates/bws";
+  cargoBuildFlags = [ "--package" "bws" ];
+
+  cargoTestFlags = [ "--package" "bws" ];
 
   postInstall = ''
     installShellCompletion --cmd bws \