`custommk/ergostrafer_rgb`: move to keyboard.json (#23990)

keyboards/custommk/ergostrafer_rgb/info.json → keyboards/custommk/ergostrafer_rgb/keyboard.json

@@ -4,6 +4,9 @@
     "maintainer": "customMK",
     "bootloader": "stm32-dfu",
     "diode_direction": "ROW2COL",
+    "audio": {
+        "driver": "pwm_hardware"
+    },
     "dynamic_keymap": {
         "layer_count": 32
     },

keyboards/custommk/ergostrafer_rgb/rules.mk

@@ -1 +0,0 @@
-AUDIO_DRIVER = pwm_hardware