Add supported_protocols to yandex geocoder

lib/geocoder/lookups/yandex.rb

@@ -15,6 +15,10 @@ module Geocoder::Lookup
     def query_url(query)
       "#{protocol}://geocode-maps.yandex.ru/1.x/?" + url_query_string(query)
     end
+    
+    def supported_protocols
+      [:https]
+    end
 
     private # ---------------------------------------------------------------