"label" keyword not supported

[pickardaa]

When trying to generate a keymap that includes labels in a keymap node, the following error is receive:

 Fetching keyboard layout.
2024-03-24T13:26:07-07:00 INF Parsing keymap file.
2024-03-24T13:26:07-07:00 ERR  error="~/zmk/config/corne.keymap:30:13: unexpected token \"label\" (expected \"}\" \";\")"
2024-03-24T13:26:07-07:00 INF Image saved Path=boardsource_unicorne_split_3x6_3.png
~/zmk$ vim config/corne.keymap
~/zmk$ zmk-viewer generate -f config/corne.keymap boardsource/unicorne

Keymap looks like this:

/*
 * Copyright (c) 2020 The ZMK Contributors
 *
 * SPDX-License-Identifier: MIT
 */

#include <behaviors.dtsi>
#include <dt-bindings/zmk/bt.h>
#include <dt-bindings/zmk/keys.h>

/ {
    
    keymap {
        compatible = "zmk,keymap";

        win_base {
            // -----------------------------------------------------------------------------------------
            // |  TAB |  Q  |  W  |  E  |  R  |  T  |   |  Y  |  U   |  I  |  O  |  P  | BKSP |
            // | CTRL |  A  |  S  |  D  |  F  |  G  |   |  H  |  J   |  K  |  L  |  ;  |  '   |
            // | SHFT |  Z  |  X  |  C  |  V  |  B  |   |  N  |  M   |  ,  |  .  |  /  | ESC  |
            //                    | GUI | LWR | SPC |   | ENT | RSE  | ALT |

            bindings = <
&kp TAB       &kp Q  &kp W  &kp E      &kp R                         &kp T        &kp Y          &kp U                       &kp I            &kp O    &kp P     &kp BSPC
&kp LSHIFT    &kp A  &kp S  &kp D      &kp F                         &kp G        &kp H          &kp J                       &kp K            &kp L    &kp SEMI  &kp SQT
&kp LEFT_WIN  &kp Z  &kp X  &kp C      &kp V                         &kp B        &kp N          &kp M                       &kp COMMA        &kp DOT  &kp FSLH  &kp ESC
                            &kp LCTRL  &hold_for_layer_shft 1 ENTER  &kp SPACE    &kp BACKSPACE  &hold_for_layer_shft 2 TAB  &kp RIGHT_SHIFT
            >;

            label = "Windows Base";
        };
    };
};