Merge pull request #457 from johnboiles/master

For ESP-IDF builds use arduino-esp32 instead of arduino dependency

CMakeLists.txt

@@ -6,6 +6,6 @@ cmake_minimum_required(VERSION 3.5)
 
 idf_component_register(SRCS "Adafruit_GFX.cpp" "Adafruit_GrayOLED.cpp" "Adafruit_SPITFT.cpp" "glcdfont.c"
                        INCLUDE_DIRS "."
-                       REQUIRES arduino Adafruit_BusIO)
+                       REQUIRES arduino-esp32 Adafruit_BusIO)
 
 project(Adafruit-GFX-Library)