Update Kotlin documentation (1.2.21)

assets/javascripts/templates/pages/about_tmpl.coffee

@@ -367,7 +367,7 @@ credits = [
     'https://raw.githubusercontent.com/knockout/knockout/master/LICENSE'
   ], [
     'Kotlin',
-    '2010-2017 JetBrains s.r.o.',
+    '2010-2018 JetBrains s.r.o.',
     'Apache',
     'https://raw.githubusercontent.com/JetBrains/kotlin/master/license/LICENSE.txt'
   ], [

lib/docs/scrapers/kotlin.rb

@@ -1,7 +1,7 @@
 module Docs
   class Kotlin < UrlScraper
     self.type = 'kotlin'
-    self.release = '1.1.4'
+    self.release = '1.2.21'
     self.base_url = 'https://kotlinlang.org/'
     self.root_path = 'api/latest/jvm/stdlib/index.html'
     self.links = {
@@ -25,7 +25,7 @@ module Docs
     options[:replace_paths] = { 'api/latest/jvm/stdlib/' => 'api/latest/jvm/stdlib/index.html' }
 
     options[:attribution] = <<-HTML
-      &copy; 2010&ndash;2017 JetBrains s.r.o.<br>
+      &copy; 2010&ndash;2018 JetBrains s.r.o.<br>
       Licensed under the Apache License, Version 2.0.
     HTML
   end