get_marker for older pytest

gistfile1.txt

diff --git a/convert2rhel/unit_tests/conftest.py b/convert2rhel/unit_tests/conftest.py
index 40ccf0b..acdd1d1 100644
--- a/convert2rhel/unit_tests/conftest.py
+++ b/convert2rhel/unit_tests/conftest.py
@@ -82,8 +82,11 @@ def system_cert_with_target_path(monkeypatch, tmpdir, request):
     .. seealso::
         https://docs.pytest.org/en/7.1.x/how-to/fixtures.html#using-markers-to-pass-data-to-fixtures
     """
+    if pytest.__version__.split('.') <= ('3', '6', '0'):
+        mark = request.node.get_marker("cert_filename")
+    else:
+        mark = request.node.get_closest_marker("cert_filename")
 
-    mark = request.node.get_closest_marker("cert_filename")
     if not mark:
         temporary_filename = "filename"
     else: