Update gemspec

Author: laurynas

detect_language.gemspec

@@ -2,19 +2,20 @@
 require File.expand_path('../lib/detect_language/version', __FILE__)
 
 Gem::Specification.new do |gem|
-  gem.authors       = ["Laurynas Butkus"]
-  gem.email         = ["[email protected]"]
-  gem.description   = %q{Language Detection API Client}
-  gem.summary       = %q{Detects language of given text. Returns detected language codes and scores.}
-  gem.homepage      = "https://github.com/detectlanguage/detectlanguage-ruby"
+  gem.authors = ['Laurynas Butkus']
+  gem.email = ['[email protected]']
+  gem.description = 'Language Detection API Client'
+  gem.summary = 'Detects language of given text. Returns detected language codes and scores.'
+  gem.homepage = 'https://github.com/detectlanguage/detectlanguage-ruby'
 
-  gem.files         = %w(LICENSE README.md detect_language.gemspec)
-  gem.files         += Dir.glob('lib/**/*.{rb}')
+  gem.files = %w(LICENSE README.md detect_language.gemspec)
+  gem.files += Dir.glob('lib/**/*.{rb}')
 
-  gem.executables   = gem.files.grep(%r{^bin/}).map{ |f| File.basename(f) }
-  gem.test_files    = gem.files.grep(%r{^(test|spec|features)/})
-  gem.name          = "detect_language"
-  gem.require_paths = ["lib"]
-  gem.version       = DetectLanguage::VERSION
-  gem.license       = 'MIT'
+  gem.executables = gem.files.grep(%r{^bin/}).map{ |f| File.basename(f) }
+  gem.test_files = gem.files.grep(%r{^(test|spec|features)/})
+  gem.name = 'detect_language'
+  gem.require_paths = ['lib']
+  gem.version = DetectLanguage::VERSION
+  gem.license = 'MIT'
+  gem.required_ruby_version = '>= 2.0.0'
 end