BUG with numbers between 0 and 1

# CODE:

````php
<?php

$chart = new Linechart();
echo $chart->addMarkers([0.1,0.9])->chart();
````
# Output:
````
   0.2┤
  -0.6┤─
````
# Expected Output:
something like this:
````
   0.9┤╭
   0.8┤│
   0.7┤│
   0.6┤│
   0.5┤│
   0.4┤│
   0.3┤│
   0.2┤│
   0.1┼╯
````
