Add I2C INA219 driver (#705)

INA219: add INA219 driver

examples/ina219/main.go

@@ -0,0 +1,29 @@
+package main
+
+import (
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers/ina219"
+)
+
+func main() {
+	machine.I2C0.Configure(machine.I2CConfig{})
+
+	dev := ina219.New(machine.I2C0)
+	dev.Configure()
+
+	for {
+		busVoltage, shuntVoltage, current, power, err := dev.Measurements()
+		if err != nil {
+			println("Error reading measurements", err)
+		}
+
+		println("Bus Voltage:", busVoltage, "V")
+		println("Shunt Voltage:", shuntVoltage/100, "mV")
+		println("Current:", current, "mA")
+		println("Power:", power, "mW")
+
+		time.Sleep(10 * time.Millisecond)
+	}
+}