Update Vendored Erubis to 2.6.6

vendor/plugins/erubis/test/data/users-guide/example5.rb

@@ -0,0 +1,16 @@
+require 'erubis'
+input = File.read('example5.eruby')
+eruby = Erubis::Eruby.new(input)      # create Eruby object
+
+## create context object
+## (key means var name, which may be string or symbol.)
+context = {
+  :val   => 'Erubis Example',
+  'list' => ['aaa', 'bbb', 'ccc'],
+}
+## or
+# context = Erubis::Context.new()
+# context['val'] = 'Erubis Example'
+# context[:list] = ['aaa', 'bbb', 'ccc'],
+
+puts eruby.evaluate(context)         # get result