Stop using deprecated interfaces

As `USE_PLUGINS` and `loop_hook_use` are getting deprecated, use the newer APIs:
`Kaleidoscope.use` and `Kaleidoscope.useLoopHook`.

Signed-off-by: Gergely Nagy <kaleidoscope@gergo.csillger.hu>

README.md

@@ -44,7 +44,7 @@ void magicComboActions(uint8_t combo_index, uint32_t left_hand, uint32_t right_h
 void setup() {
   Serial.begin(9600);
 
-  USE_PLUGINS(&MagicCombo);
+  Kaleidoscope.use(&MagicCombo);
 
   Kaleidoscope.setup();
 

examples/MagicCombo/MagicCombo.ino

@@ -59,7 +59,7 @@ const Key keymaps[][ROWS][COLS] PROGMEM = {
 void setup() {
   Serial.begin(9600);
 
-  USE_PLUGINS(&MagicCombo);
+  Kaleidoscope.use(&MagicCombo);
 
   Kaleidoscope.setup();
 

src/Kaleidoscope/MagicCombo.cpp

@@ -38,7 +38,7 @@ MagicCombo::MagicCombo(void) {
 }
 
 void MagicCombo::begin(void) {
-  loop_hook_use(loopHook);
+  Kaleidoscope.useLoopHook(loopHook);
 }
 
 void MagicCombo::loopHook(bool is_post_clear) {