Use "become: True" when installing ansible collections

These are now installed into /etc/ansible [1] which is only writable
by the root user, not the unpriviledged zuul user so we must
elevate priviledges to run ansible-galaxy.

[1] https://review.opendev.org/c/openstack/openstack-ansible-tests/+/925746

Change-Id: Ie20f1a076f9646bf91ed721a2a9154f989a3b19c

get-ansible-collection-requirements.yml

@@ -60,6 +60,7 @@
         dest: "{{ collection_requirements_tmpfile.path }}"
 
     - name: Install collection requirements with ansible galaxy
+      become: True
       command: >
         {{ ansible_venv | ternary(ansible_venv, '/usr') }}/bin/ansible-galaxy collection install --force
         -r "{{ collection_requirements_tmpfile.path }}" -p /etc/ansible