os_images: rc assert bug fix (#49)

* os_images: rc assert fix

* bump collection version

Author: bbezak

galaxy.yml

@@ -1,7 +1,7 @@
 ---
 namespace: stackhpc
 name: openstack
-version: 0.2.3
+version: 0.2.4
 readme: README.md
 authors:
   - StackHPC Ltd

roles/os_images/tasks/prechecks.yml

@@ -10,7 +10,7 @@
 - name: Display warning message about the container engine
   ansible.builtin.assert:
     that:
-      - result.rc = 0
+      - result.rc == 0
     fail_msg: >
       Container runtime engine could not be found - make sure it is installed.
       Elements that depend on it will likely fail when building.