doc: update instructions for linux

deploy.sh

@@ -39,6 +39,7 @@ then
 fi
 for FILE in /dev/tty.*
 do
+    # Check for port on macOS
     if check_port $FILE 
     then
         PORT=$FILE
@@ -46,6 +47,14 @@ do
     fi
 done
 if [ -z "$PORT" ]
+then
+    # Check for port on linux
+    if check_port /dev/ttyUSB0
+    then
+        PORT=/dev/ttyUSB0
+    fi
+fi
+if [ -z "$PORT" ]
 then
     echo "ESP likely not connected! Exiting now."
     echo "Make sure the ESP is connected with a data USB cable, and try again."