add I2C_INT & reorder

Add `I2C_INT` to `motor2040.hpp` and put pin defs in numeric order.

Author: robberwick

libraries/motor2040/motor2040.hpp

@@ -47,11 +47,12 @@ namespace motor {
     const uint LED_DATA = 18;
     const uint NUM_LEDS = 1;
 
-    const uint USER_SW = 23;
-
+    const uint I2C_INT = 19;
     const uint I2C_SDA = 20;
     const uint I2C_SCL = 21;
 
+    const uint USER_SW = 23;
+
     const uint ADC_ADDR_0 = 22;
     const uint ADC_ADDR_1 = 24;
     const uint ADC_ADDR_2 = 25;