ipatests: webui: Specify configuration loader
Default YAML loader has been deprecated in PyYAML-6.0, specify loader explicitly.
Fixes: https://pagure.io/freeipa/issue/9009
Signed-off-by: Michal Polovka <mpolovka@redhat.com>
Reviewed-By: Michal Polovka <mpolovka@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>