[skip]Set required ruby version to be >= 2.0(1m)

Author: Gary Hall and Matthew Kobs

openxml-docx.gemspec

@@ -19,7 +19,7 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.required_ruby_version = "~> 2.0"
+  spec.required_ruby_version = ">= 2.0"
 
   spec.add_dependency "nokogiri"
   spec.add_dependency "openxml-package", ">= 0.2.2"