update npm version

Author: anandkumarpatel

ansible/group_vars/alpha-workers.yml

@@ -8,7 +8,7 @@ container_tag: "{{ git_branch }}"
 repo: "git@github.com:CodeNow/api.git"
 
 node_version: "0.10.38"
-npm_version: "2.1.18"
+npm_version: "2.8.3"
 
 datadog_host: "{{ ansible_default_ipv4.address }}"