Update Crystal documentation (0.21.0)

assets/javascripts/templates/pages/about_tmpl.coffee

@@ -186,7 +186,7 @@ credits = [
     'https://creativecommons.org/licenses/by-sa/2.5/'
   ], [
     'Crystal',
-    '2012-2016 Manas Technology Solutions',
+    '2012-2017 Manas Technology Solutions',
     'Apache',
     'https://raw.githubusercontent.com/crystal-lang/crystal/master/LICENSE'
   ], [

lib/docs/scrapers/crystal.rb

@@ -1,7 +1,7 @@
 module Docs
   class Crystal < UrlScraper
     self.type = 'crystal'
-    self.release = '0.20.3'
+    self.release = '0.21.0'
     self.base_url = 'https://crystal-lang.org/'
     self.root_path = "api/#{release}/index.html"
     self.initial_paths = %w(docs/index.html)
@@ -29,7 +29,7 @@ module Docs
         HTML
       else
         <<-HTML
-          &copy; 2012&ndash;2016 Manas Technology Solutions.<br>
+          &copy; 2012&ndash;2017 Manas Technology Solutions.<br>
           Licensed under the Apache License, Version 2.0.
         HTML
       end