update the requirement.txt to ansible 2.x

playbooks/roles/launch_ec2/tasks/main.yml

@@ -51,11 +51,12 @@
     image: "{{ ami }}"
     vpc_subnet_id: "{{ vpc_subnet_id }}"
     assign_public_ip: yes
-    wait: true
+    wait: True
     region: "{{ region }}"
     instance_tags: "{{ instance_tags }}"
     volumes:
       - device_name: /dev/sda1
+        volume_type: gp2
         volume_size: "{{ root_ebs_size }}"
         delete_on_termination: true
     zone: "{{ zone }}"