Fix xiao rp2040 pin variable assignment

According to official infomation(https://wiki.seeedstudio.com/XIAO-RP2040/), D9 and D10 are corresponding to GPIO4 and GPIO3, respectively.
2022-11-20 10:20:24 +09:00 · 2022-11-20 10:20:24 +09:00 · a329f56ec2
--- a/src/machine/board_xiao-rp2040.go
+++ b/src/machine/board_xiao-rp2040.go
@ -24,8 +24,8 @@ const (
 	D6  Pin = GPIO0
 	D7  Pin = GPIO1
 	D8  Pin = GPIO2
-	D9  Pin = GPIO3
+	D9  Pin = GPIO4
-	D10 Pin = GPIO4
+	D10 Pin = GPIO3
 )
 // Analog pins