Updated watir-webdriver Ruby gem to the latest version

Also updated other gems, except mediawiki_selenium (only patch version
update) and rubocop.

Ignoring folders created by mediawiki-vagrant.

Bug: T112748
Change-Id: I95f7611141e42c89cacdd3abec3b5f94f7e8f3de

Gemfile

@@ -1,7 +1,4 @@
-#ruby=ruby-2.1.2
-#ruby-gemset=UniversalLanguageSelector
-
 source "https://rubygems.org"
 
 gem 'mediawiki_selenium', '~> 0.4.2'
-gem "rubocop", require: false
+gem "rubocop", "~> 0.29.1", require: false