remove github link in sidebar (#268)

Author: jwmueller

docs/source/_templates/brand.html

@@ -18,8 +18,3 @@
     {%- endif %}
     {% endblock brand_content %}
 </a>
-
-<div style="margin-left: 12px; margin-top: 4px;">
-    <a style="margin-top: 6px;" class="github-button" href="https://github.com/cleanlab/cleanvision" data-size="large" data-show-count="true"
-    aria-label="Star cleanlab/cleanvision on GitHub">GitHub</a>
-</div>