Update _reading-time.liquid

_includes/_reading-time.liquid

 {% assign reading_wpm = 200 %} 
 {% assign word_count = page.content | split: " " | size %}
-{% assign reading_time = word_count | divided_by: 200 %}
+{% assign reading_time = word_count | divided_by: reading_wpm %}
 {% case reading_time %}
   {% when 0 %}
     {% assign phrase = "less than a minute." %}
   {% when 1 %}
     {% assign phrase = "about a minute." %}
-                          {% else %}								
+  {% else %}								
     {% assign phrase = " minutes." | prepend: reading_time %}
 {% endcase %}
 <div class="post-meta"><time pubdate="pubdate">{{ page.published_date | date: "%b %d, %Y" }} - Reading time: {{ phrase }}</time></div><br />