Added st2workflowengine

[nmaludy]

Closes #196
Added st2workflowengine to the list of services for 2.8.0 release

[Kami]

LGTM.

Do we need any other changes to support this new service? Or is this it?

[arm4b]

Yes, this should be enough, since the st2_services list is referenced in other places like

ansible-st2/roles/st2/handlers/main.yml

Lines 1 to 6 in 25f8098

	- name: restart st2
	become: yes
	service:
	name: "{{ item }}"
	state: restarted
	with_items: "{{ st2_services }}"

and

ansible-st2/roles/st2/tasks/main.yml

Lines 87 to 94 in f89ab61

	- name: Ensure StackStorm services are enabled and running
	become: yes
	service:
	name: "{{ item }}"
	enabled: yes
	state: started
	with_items: "{{ st2_services }}"
	tags: st2

[arm4b]

Thanks again for PR! 👍