My Sign In nav item doesnt align to the right in Bootstrap

My Sign In nav item doesn't align to the right in Bootstrap, i tried float-right, text-right, mr-auto, ml-auto etc

Is there a more flexbox-ish way to right-align "Contact" than to use position: absolute?

My code is below:

<!DOCTYPE html>
<html lang="en">
<head>
  <title>QuadCodeSchools</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="icon" href="logo.jpg">
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js"></script>
</head>
<style>


</style>
<body>

<nav class="navbar navbar-expand-md bg-dark navbar-dark">

     <img src="logo.jpg" alt="Logo" style="width:40px;">
  <a class="navbar-brand" href="#">QuadCodeSchools</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#collapsibleNavbar">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="collapsibleNavbar">
    <ul class="navbar-nav">
      <li class="nav-item">
        <a class="nav-link" href="#">Home</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Courses</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Donate</a>
      </li>    
      <div >
      <li class="nav-item mr-auto">

        <a class="nav-link" href="#" class="float-right">Sign In</a>
      </li>  
    </div>
    </ul>
  </div>  
</nav>
<br>

</body>
</html>

I will appreciate if I can get an answer. GitHub Link