corrects A3 from pin 3 to pin 18(C18), adds A7 as pin 16(C16), updates comment (#521)

Author: fabianhugo

variants/CalliopeminiV3/variant.cpp

@@ -27,7 +27,7 @@ const uint32_t g_ADigitalPinMap[] = {
   17, // SCK
   1,  // MISO
   13, // MOSI
-  29, // A5, C16_A1RX (Calliope change)
+  29, // A7, C16_A1RX (Calliope change)
 
   // 17 + 18
   34, // P1.02 C17 (Calliope exclusive pin)

variants/CalliopeminiV3/variant.h

@@ -34,10 +34,11 @@ extern "C"
 #define PIN_A0				(0)
 #define PIN_A1				(1)
 #define PIN_A2				(2)
-#define PIN_A3				(3)
+#define PIN_A3				(18)
 #define PIN_A4				(4)
 #define PIN_A5				(10)
 #define PIN_A6				(29)
+#define PIN_A7				(16)
 
 #define ADC_RESOLUTION 10
 static const uint8_t A0 = PIN_A0;
@@ -47,6 +48,7 @@ static const uint8_t A3 = PIN_A3;
 static const uint8_t A4 = PIN_A4;
 static const uint8_t A5 = PIN_A5;
 static const uint8_t A6 = PIN_A6;
+static const uint8_t A7 = PIN_A7;
 
 // Serial