docs: update example

Author: antonfisher

README.md

@@ -61,9 +61,11 @@ func main() {
 
   // Create driver for Adafruit 15x7 CharliePlex LED Matrix FeatherWing
   // (CharlieWing): https://www.adafruit.com/product/3163
-  ledMatrix, err := is31fl3731.NewAdafruitCharlieWing15x7(bus, I2CAddress)
+  ledMatrix := is31fl3731.NewAdafruitCharlieWing15x7(bus, I2CAddressLEDMatrix)
+
+  err = ledMatrix.Configure()
   if err != nil {
-    println("could not create driver:", err)
+    println("could not configure led driver:", err)
     return
   }