Loosen dependency on childprocess in ruby gemspec

Author: connorshea

rb/selenium-webdriver.gemspec

@@ -31,7 +31,7 @@ Gem::Specification.new do |s|
   s.files = Dir[root + '/**/*'].reject { |e| e =~ /ruby\.iml|build\.desc/ }.map { |e| e.sub(root + '/', '') }
   s.require_paths = ['lib']
 
-  s.add_runtime_dependency 'childprocess', ['>= 0.5', '< 3.0']
+  s.add_runtime_dependency 'childprocess', ['>= 0.5', '< 4.0']
   s.add_runtime_dependency 'rubyzip', ['>= 1.2.2']
 
   # childprocess requires ffi on windows but doesn't declare it in its dependencies