Merge pull request #1030 from t-woerner/use_yml_extension_for_pytest_tests

tests/pytests/conftest.py

...e/playbooks/dnszone_add_multiple_ipv4_ipv6_forwarders.yml

...tests/dnszone/playbooks/dnszone_add_without_forwarder.yml

tests/pytests/dnszone/playbooks/dnszone_del_multiple.yml

tests/pytests/dnszone/playbooks/dnszone_disable.yml

tests/pytests/dnszone/playbooks/dnszone_enable.yml

tests/pytests/dnszone/playbooks/dnszone_invalid_ip.yml

tests/pytests/dnszone/playbooks/dnszone_invalid_serial.yml

tests/pytests/dnszone/playbooks/dnszone_name_from_ip.yml

...ts/dnszone/playbooks/dnszone_with_forward_policy_only.yml

tests/pytests/dnszone/test_dnszone.py