Update graphs.html

docs/graphs.html

@@ -395,7 +395,7 @@ <h2><span class="header-section-number">5.1</span> Resources</h2>
 <li><p><a href="http://www.cookbook-r.com/Graphs/">R Graphics Cookbook</a></p></li>
 <li><p><a href="http://www.r-graph-gallery.com/portfolio/ggplot2-package/">R graph gallery</a></p></li>
 <li><p><a href="http://motioninsocial.com/tufte/">Tufte in R</a></p></li>
-<li><p><a href="http://www.ggplot2-exts.org/gallery/">ggplot2 extensions</a></p></li>
+<li><p><a href="https://exts.ggplot2.tidyverse.org//">ggplot2 extensions</a></p></li>
 <li><p><a href="https://cran.r-project.org/web/packages/ggthemes/vignettes/ggthemes.html">ggthemes Vignette</a></p></li>
 <li><p><a href="https://www.rstudio.com/wp-content/uploads/2015/03/ggplot2-cheatsheet.pdf">ggplot2 cheatsheet</a></p></li>
 </ul>