Use /dev/tty on OSX rather than /dev/cu

See https://stackoverflow.com/questions/8632586/macos-whats-the-difference-between-dev-tty-and-dev-cu/8632603

proxmark3.sh

@@ -21,7 +21,7 @@ function wait4proxmark_Linux {
 function wait4proxmark_macOS {
     echo >&2 "[=] Waiting for Proxmark3 to appear..."
     while true; do
-        PM3=$(find /dev/pm3-* /dev/cu.usbmodem* 2>/dev/null | head -1)
+        PM3=$(find /dev/pm3-* /dev/tty.usbmodem* 2>/dev/null | head -1)
         if [[ $PM3 != "" ]]; then
             break
         fi