.github/workflows/docs.yml: Enable verbose mode for ansible-doc-test

Currently ansible-doc-test is run silently. There is no output about
the checked files in the test results. Therefore verbose mode has been
enabled.

.github/workflows/docs.yml

@@ -15,7 +15,7 @@ jobs:
       - name: Run ansible-doc-test
         run: |
           python -m pip install "ansible < 2.10"
-          ANSIBLE_LIBRARY="." python utils/ansible-doc-test roles plugins
+          ANSIBLE_LIBRARY="." python utils/ansible-doc-test -v roles plugins
   
   check_docs_latest:
     name: Check Ansible Documentation with latest Ansible.