upgraded jekyll and bundle

_plugins/image-reference-update.rb

@@ -1,6 +1,7 @@
 require 'uri'
 require 'faraday'
 require 'yaml'
+require 'date'
 require 'mini_magick'
 
 class Localizer
@@ -49,14 +50,17 @@ class Localizer
 
   # helper to make sure that we can follow redirects, which can be important for
   # many of the cloud file sharing services out there.
-  def download_file_helper(connection, url)
-    response = connection.get do |req|
-      req.url(url)
-    end
+  def download_file_helper(connection, url, redirect_limit = 5)
+    raise "Too many redirects while downloading #{url}" if redirect_limit <= 0
+
+    response = connection.get(url)
 
     case response.status
-    when 302
-      download_file_helper(connection, response['Location'])
+    when 301, 302, 303, 307, 308
+      location = response.headers['location']
+      raise "Redirect received without Location header for #{url}" unless location
+
+      download_file_helper(connection, location, redirect_limit - 1)
     when 200
       response
     else
@@ -70,7 +74,7 @@ class Localizer
     contents = File.read(file, encoding: 'UTF-8')
 
     # Step 1: get all the images that must be downloaded
-    yaml = YAML.load(contents)
+    yaml = YAML.safe_load(contents, permitted_classes: [Date], aliases: true)
 
     yaml['talks'].each do |talk|
      IMAGE_FIELDS.each do |image_field|