Merge pull request #2310 from andrehjr/method-source-for-earlier-rubies

Make sure method_source stays at 1.0.0 for RUBY < 2.3

Gemfile

@@ -9,6 +9,10 @@ gem 'rspec'
 
 gem "psych", '<= 5.1.0'
 
+if Gem::Version.new(RUBY_VERSION) < Gem::Version.new('2.3.0')
+  gem 'method_source', '= 1.0.0'
+end
+
 # Rubocop supports only >=2.2.0
 if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.2.0')
   gem 'rubocop', '= 0.66.0', require: false