Skip manifest test on ancient podman versions

It fails with "manifest type not supported"

tests/test_metadata.py

@@ -87,6 +87,7 @@
 from bci_tester.data import SPACK_CONTAINERS
 from bci_tester.data import TOMCAT_CONTAINERS
 from bci_tester.data import ImageType
+from bci_tester.runtime_choice import PODMAN_SELECTED
 
 #: The official vendor name
 VENDOR = "openSUSE Project" if OS_VERSION == "tumbleweed" else "SUSE LLC"
@@ -647,6 +648,9 @@ def test_reference(
 
 
 @SKIP_IF_TW_MARK
+@pytest.mark.skipif(
+    not PODMAN_SELECTED, reason="we only need to test it for one runtime"
+)
 @pytest.mark.parametrize("container", ALL_CONTAINERS, indirect=True)
 def test_oci_base_refs(
     container: ContainerData,
@@ -674,7 +678,9 @@ def test_oci_base_refs(
     ), "Base image reference is not the expected version"
     assert base_digest.startswith("sha256:")
 
-    LOCALHOST.run_expect(
-        [0],
+    if container_runtime.version.major < 3:
+        pytest.skip("Podman version too old for checking")
+
+    LOCALHOST.check_output(
         f"{container_runtime.runner_binary} manifest inspect {base_repository}@{base_digest}",
     )