Stop calling obsolete method: URI.escape

No escaping should be necessary, according to the MaxMind docs:
http://dev.maxmind.com/geoip/geoip2/web-services/

lib/geocoder/lookups/maxmind_geoip2.rb

@@ -15,7 +15,7 @@ module Geocoder::Lookup
     end
 
     def query_url(query)
-      "#{protocol}://geoip.maxmind.com/geoip/v2.1/#{configured_service!}/#{URI.escape(query.sanitized_text.strip)}"
+      "#{protocol}://geoip.maxmind.com/geoip/v2.1/#{configured_service!}/#{query.sanitized_text.strip}"
     end
 
     private # ---------------------------------------------------------------