upgrade version number

Author: fmichonneau

_includes/lesson_footer.html

@@ -45,7 +45,7 @@
   <div class="row">
     <div class="col-md-12" align="center">
       Using <a href="https://github.com/carpentries/styles/">The Carpentries style</a>
-      version <a href="https://github.com/carpentries/styles/releases/tag/v9.5.2">9.5.2</a>.
+      version <a href="https://github.com/carpentries/styles/releases/tag/v9.5.3">9.5.3</a>.
     </div>
   </div>
 </footer>