add secure protocol

Author: LauraKirby

map.md

@@ -2,10 +2,10 @@
 layout: default
 title: Workshop Locations
 ---
-<link rel="stylesheet" type="text/css" href="http://bridgefoundry.org/workshop-map/workshop-map.css">
-<script src="http://d3js.org/d3.v4.min.js"></script>
-<script src="http://d3js.org/topojson.v2.min.js"></script>
-<script src="http://bridgefoundry.org/workshop-map/workshop-map.js" type="text/javascript"></script>
+<link rel="stylesheet" type="text/css" href="https://bridgefoundry.org/workshop-map/workshop-map.css">
+<script src="https://d3js.org/d3.v4.min.js"></script>
+<script src="https://d3js.org/topojson.v2.min.js"></script>
+<script src="https://bridgefoundry.org/workshop-map/workshop-map.js" type="text/javascript"></script>
 
 <div id="map"></div>
 <script>