Fix footer links (#30)

Author: pavithraes

_includes/footer.html

@@ -8,7 +8,7 @@
         </p>
         <p>
           ©{{ site.time | date: '%Y' }} Bokeh contributors.
-          The website content uses the <a href="https://github.com/bokeh/bokeh.org/blob/master/LICENSE.txt">BSD License</a> and is covered by the <a href="https://github.com/bokeh/bokeh/blob/master/CODE_OF_CONDUCT.md">Bokeh Code of Conduct</a>.
+          The website content uses the <a href="https://github.com/bokeh/bokeh.org/blob/main/LICENSE.txt">BSD License</a> and is covered by the <a href="https://github.com/bokeh/bokeh/blob/main/docs/CODE_OF_CONDUCT.md">Bokeh Code of Conduct</a>.
         </p>
       </div>
       <br />