Upgrade python

Author: hgreebe

cookbooks/aws-parallelcluster-shared/resources/install_pyenv.rb

@@ -14,7 +14,7 @@
 
 action :run do
   python_version = new_resource.python_version || node['cluster']['python-version']
-  python_url = "#{node['cluster']['artifacts_s3_url']}/dependencies/python/Python-#{python_version}.tgz"
+  python_url =  "https://www.python.org/ftp/python/#{python_version}/Python-#{python_version}.tgz"
 
   if !aws_region.start_with?("us-iso") && new_resource.python_version
     python_url = "https://www.python.org/ftp/python/#{python_version}/Python-#{python_version}.tgz"