[Keyboard] Add Frost68 keyboard (#20370)

Co-authored-by: Pablo Martínez <58857054+elpekenin@users.noreply.github.com>
Co-authored-by: Drashna Jaelre <drashna@live.com>
Co-authored-by: Joel Challis <git@zvecr.com>
Co-authored-by: jack <0x6a73@protonmail.com>

keyboards/skeletonkbd/frost68/frost68.c

@@ -0,0 +1,18 @@
+// Copyright 2023 skeletonkbd (@skeletonkbd)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "quantum.h"
+
+bool rgb_matrix_indicators_advanced_kb(uint8_t led_min, uint8_t led_max) {
+    if (!rgb_matrix_indicators_advanced_user(led_min, led_max)) {
+        return false;
+    }
+    if (host_keyboard_led_state().caps_lock) {
+        for (uint8_t i = led_min; i < led_max; i++) {
+            if (g_led_config.flags[i] & LED_FLAG_INDICATOR) {
+                rgb_matrix_set_color(i, RGB_RED);
+            }
+        }
+    }
+    return false;
+}