Update the Breadcrumb module

At the moment, this is the only possible method:

<div class="breadcrumb">
    <a class="breadcrumb-item breadcrumb-link" href="#">Home</a>
    <a class="breadcrumb-item breadcrumb-link" href="#">Library</a>
    <a class="breadcrumb-item breadcrumb-link active" href="#">Data</a>
</div>

This is what the current Bootstrap documentation suggests:

<nav aria-label="breadcrumb">
    <ol class="breadcrumb">
        <li class="breadcrumb-item"><a href="#">Home</a></li>
        <li class="breadcrumb-item"><a href="#">Library</a></li>
        <li class="breadcrumb-item active" aria-current="page">Data</li>
    </ol>
</nav>