Update PHPUnit documentation (6.5)

Author: Thibaut

lib/docs/scrapers/phpunit.rb

@@ -24,7 +24,7 @@ class Phpunit < UrlScraper
     HTML
 
     version '6' do
-      self.release = '6.4'
+      self.release = '6.5'
       self.base_url = "https://phpunit.de/manual/#{release}/en/"
     end