Update 503.html - replace http with https (#6562)

public/503.html

@@ -10,7 +10,7 @@
     <link href="/assets/application.css" media="all" rel="stylesheet" type="text/css" />
     <!-- Le HTML5 shim, for IE6-8 support of HTML5 elements -->
     <!--[if lt IE 9]>
-      <script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script>
+      <script src="https://html5shim.googlecode.com/svn/trunk/html5.js"></script>
     <![endif]-->
     <script src="https://code.jquery.com/jquery-3.3.1.min.js" type="text/javascript"></script>
     <script src="/assets/application.js" type="text/javascript"></script>
@@ -107,12 +107,12 @@ <h4>Links</h4>
         </ul>
       </div>
       <div class="col-md-3">
-        <a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/"><img alt="Creative Commons License" style="border-width:0;float:left;margin-right:10px;" src="/images/cc-by-sa-88x31.png" /></a>
-        <p>This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/">Creative Commons Attribution-ShareAlike 3.0 Unported License</a>. Hardware designs on this site are released under the <a href="http://www.ohwr.org/cernohl">CERN Open Hardware License 1.1</a>. Read more about Public Laboratory's <a href="/licenses">open source licensing here</a>.</p>
+        <a rel="license" href="https://creativecommons.org/licenses/by-sa/3.0/"><img alt="Creative Commons License" style="border-width:0;float:left;margin-right:10px;" src="/images/cc-by-sa-88x31.png" /></a>
+        <p>This work is licensed under a <a rel="license" href="https://creativecommons.org/licenses/by-sa/3.0/">Creative Commons Attribution-ShareAlike 3.0 Unported License</a>. Hardware designs on this site are released under the <a href="https://www.ohwr.org/cernohl">CERN Open Hardware License 1.1</a>. Read more about Public Laboratory's <a href="/licenses">open source licensing here</a>.</p>
       </div>
       <div class="col-md-3 hidden-print">
         <p>Specific works on this site may be released or dedicated under different licenses, but only if such alternatives are clearly indicated by their authors.</p>
-        <p>This site makes extensive use of the open source font <a href="http://www.theleagueofmoveabletype.com/junction">Junction</a>.</p>
+        <p>This site makes extensive use of the open source font <a href="https://www.theleagueofmoveabletype.com/junction">Junction</a>.</p>
       </div>
       <br style="clear:both;" />
     </footer>