style: add some margin around progress bar

output/about/index.md

@@ -21,7 +21,7 @@ We also attempt to filter out notes for deleted tweets and non-English tweets.
 
 {% assign perc_fetched = site.data.meta.total_fetched | times: 100 | divided_by: site.data.meta.total_notes %}
 
-<div class="progress" style="max-width: 500px;" role="progressbar">
+<div class="progress my-2" style="max-width: 500px;" role="progressbar">
   <div class="progress-bar text-bg-{% if perc_fetched == 100 %}success{% else %}warning{% endif %}" style="width: {{ perc_fetched }}%">{{ perc_fetched }}% ({{ site.data.meta.total_fetched }} / {{ site.data.meta.total_notes }})</div>
 </div>