Use standard delimiters

Gemfile

@@ -1,8 +1,8 @@
 # frozen_string_literal: true
 
-source 'https://rubygems.org'
+source "https://rubygems.org"
 
 gemspec
 
-gem "rubocop", "1.12.1", require: false
-gem 'rubocop-rspec', require: false
+gem "rubocop", require: false
+gem "rubocop-rspec", require: false

whois.gemspec

@@ -1,18 +1,18 @@
 # -*- encoding: utf-8 -*-
-$:.push File.expand_path('../lib', __FILE__)
-require 'whois/version'
+$:.push File.expand_path("../lib", __FILE__)
+require "whois/version"
 
 Gem::Specification.new do |s|
-  s.name        = 'whois'
+  s.name        = "whois"
   s.version     = Whois::VERSION
-  s.authors     = ['Simone Carletti']
-  s.email       = ['[email protected]']
-  s.homepage    = 'https://whoisrb.org/'
-  s.summary     = 'An intelligent pure Ruby WHOIS client and parser.'
-  s.description = 'Whois is an intelligent WHOIS client and parser written in pure Ruby. It can query registry data for IPv4, IPv6 and top level domains, and parse the responses into easy-to-use Ruby objects via the whois-parser library.'
-  s.license     = 'MIT'
+  s.authors     = ["Simone Carletti"]
+  s.email       = ["[email protected]"]
+  s.homepage    = "https://whoisrb.org/"
+  s.summary     = "An intelligent pure Ruby WHOIS client and parser."
+  s.description = "Whois is an intelligent WHOIS client and parser written in pure Ruby. It can query registry data for IPv4, IPv6 and top level domains, and parse the responses into easy-to-use Ruby objects via the whois-parser library."
+  s.license     = "MIT"
 
-  s.required_ruby_version = '>= 2.4'
+  s.required_ruby_version = ">= 2.4"
 
   s.require_paths    = %w( lib )
   s.executables      =%w( whoisrb )