Remove site title from copyright in the footer (#57)

Author: HofiOne

_includes/footer.html

@@ -18,4 +18,4 @@
   </ul>
 </div>
 
-<div class="page__footer-copyright">&copy; {{ site.time | date: '%Y' }} {{ site.name | default: site.title }}. {{ site.data.ui-text[site.locale].powered_by | default: "Powered by" }} <a href="https://jekyllrb.com" rel="nofollow" target="_blank">Jekyll</a>, <a href="https://mademistakes.com/work/minimal-mistakes-jekyll-theme/" rel="nofollow" target="_blank">Minimal Mistakes</a> &amp; <a href="https://lunrjs.com/" rel="nofollow" target="_blank">Lunr</a>.</div>
+<div class="page__footer-copyright">&copy; {{ site.time | date: '%Y' }} {{ site.data.ui-text[site.locale].powered_by | default: "Powered by" }} <a href="https://jekyllrb.com" rel="nofollow" target="_blank">Jekyll</a>, <a href="https://mademistakes.com/work/minimal-mistakes-jekyll-theme/" rel="nofollow" target="_blank">Minimal Mistakes</a> &amp; <a href="https://lunrjs.com/" rel="nofollow" target="_blank">Lunr</a>.</div>