Workaround scp behaviour in OpenSSH 9.0

scp in OpenSSH 9 now uses SFTP by default, which breaks the Packer /
Ansible / SSH Proxy interaction

See hashicorp/packer-plugin-ansible#100
And hashicorp/packer#11783

Adding the `-O` flag to  the `scp` command forces the old protocol to be
used.

images/capi/packer/qemu/packer.json

@@ -55,6 +55,7 @@
         "ANSIBLE_SSH_ARGS='{{user `existing_ansible_ssh_args`}} -o IdentitiesOnly=yes'"
       ],
       "extra_arguments": [
+        "--scp-extra-args", "'-O'",
         "--extra-vars",
         "{{user `ansible_common_vars`}}",
         "--extra-vars",
@@ -79,6 +80,7 @@
         "ANSIBLE_SSH_ARGS='{{user `existing_ansible_ssh_args`}} -o IdentitiesOnly=yes'"
       ],
       "extra_arguments": [
+        "--scp-extra-args", "'-O'",
         "--extra-vars",
         "{{user `ansible_common_vars`}}",
         "--extra-vars",