Add warning about Python 3.13 not being tested

Signed-off-by: Joaquin Anton Guirao <janton@nvidia.com>

dali/python/nvidia/dali/backend.py

@@ -55,6 +55,11 @@ def deprecation_warning(what):
             "Please update your environment to use Python 3.8, "
             "3.9, 3.10, or (experimentally) 3.11."
         )
+    # py3.13 warning
+    if sys.version_info[0] == 3 and sys.version_info[1] == 13:
+        deprecation_warning(
+            "Python 3.13 support is experimental and not officially tested."
+        )
 
     if int(str(__cuda_version__)[:2]) < 11:
         deprecation_warning(