Update to newest chef gem as a dev dependency

knife-azure.gemspec

@@ -17,7 +17,6 @@ Gem::Specification.new do |s|
   s.files = %w(LICENSE README.md) + Dir.glob("lib/**/*")
   s.homepage = "http://github.com/opscode/knife-azure"
   s.require_paths = ["lib"]
-  s.add_dependency(%q<chef>, [">= 0.10.0"])
   s.add_dependency(%q<rdoc>, ["~> 3.12"])
   s.add_dependency(%q<bundler>, [">= 0"])
   s.add_dependency(%q<rubygems-bundler>, ["~> 1.0.3"])
@@ -25,5 +24,6 @@ Gem::Specification.new do |s|
   s.add_dependency(%q<nokogiri>,[">= 1.5.5"])
   s.add_dependency(%q<knife-windows>,[">= 0"])
 
+  s.add_development_dependency(%q<chef>, [">= 11.8.2"])  
   s.add_development_dependency "mixlib-config", "~> 2.0"
 end