Change month

{% for year, items in sort_by_year(posts) %}
  <h2>{{ year }}</h2>
  <ul class="posts">
    {% for post in items %}
      <li>
        <article itemscope itemtype="http://schema.org/Article">
          <time datetime="{{ post.created_at }}">{{
post.created_at.strftime('%d %b') }}</time> <a href="{{ post.permalink
}}" class="permalink">{{ post.title }}</a>
          <div class="post-tags">
            {{ post.tags|format_tags(humanize=True) }}
          </div>
        </article>
      </li>
    {% endfor %}
  </ul>
{% endfor %}