Try to speed up the DH parameter generation.

Ansible/tasks/renew-cert.yaml

@@ -184,6 +184,10 @@
         # yamllint enable rule:line-length
         mode: 0o0644
         path: *dhparams
+        # It takes a considerable amount of time to generate new DH parameters.
+        # Try using the openssl backend instead of the Python Cryptography one
+        # to speed it up.
+        select_crypto_backend: openssl
         size: 4096
         state: present
       notify: '{{ handlers|default([]) }}'