use unpkg for all non http marker locations (#544)

* use unpkg for all non http marker locations

* added news

* make sure to install leaflet before making docs

* docs_update

Author: schloerke

NEWS

@@ -3,6 +3,7 @@ leaflet 2.0.0.9000
 
 BUG FIXES
 
+* Default marker icon locations will now use unpkg.com instead of the leaflet cdn when using https or file protocols. (#544)
 * `.leaflet-map-pane` `z-index` switched to 'auto'. Allows for map panes to appear above the map if they appear later in the dom. (#537)
 * Use correct Leaflet.js scale control remove method (#547)