Configure boards to use development_board - P (#25317)

keyboards/plum47/keyboard.json

@@ -2,7 +2,7 @@
     "manufacturer": "Masayuki Takagi",
     "keyboard_name": "plum47",
     "maintainer": "awh-tokyo",
-    "bootloader": "caterina",
+    "development_board": "promicro",
     "diode_direction": "COL2ROW",
     "features": {
         "bootmagic": true,
@@ -14,7 +14,6 @@
         "cols": ["F4", "F5", "F6", "F7", "B1", "B3", "B2", "B6", "B5", "B4", "E6", "D7"],
         "rows": ["D1", "D0", "D4", "C6"]
     },
-    "processor": "atmega32u4",
     "url": "ihttps://github.com/takagi/plum47_buildguide",
     "usb": {
         "device_version": "1.0.0",