Avoid Python 3.9 with_stem (#3589)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

.github/workflows/ci.yaml

@@ -20,7 +20,6 @@ jobs:
       matrix:
         os: [ubuntu-latest]
         python-version: ['3.11']
-        model: [yolov5n]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4

ultralytics/nn/tasks.py

@@ -684,7 +684,7 @@ def yaml_model_load(path):
     if path.stem in (f'yolov{d}{x}6' for x in 'nsmlx' for d in (5, 8)):
         new_stem = re.sub(r'(\d+)([nslmx])6(.+)?$', r'\1\2-p6\3', path.stem)
         LOGGER.warning(f'WARNING ⚠️ Ultralytics YOLO P6 models now use -p6 suffix. Renaming {path.stem} to {new_stem}.')
-        path = path.with_stem(new_stem)
+        path = path.with_name(new_stem + path.suffix)
 
     unified_path = re.sub(r'(\d+)([nslmx])(.+)?$', r'\1\3', str(path))  # i.e. yolov8x.yaml -> yolov8.yaml
     yaml_file = check_yaml(unified_path, hard=False) or check_yaml(path)

ultralytics/yolo/engine/exporter.py

@@ -591,7 +591,7 @@ class Exporter:
         # Remove/rename TFLite models
         if self.args.int8:
             for file in f.rglob('*_dynamic_range_quant.tflite'):
-                file.rename(file.with_stem(file.stem.replace('_dynamic_range_quant', '_int8')))
+                file.rename(file.with_name(file.stem.replace('_dynamic_range_quant', '_int8') + file.suffix))
             for file in f.rglob('*_integer_quant_with_int16_act.tflite'):
                 file.unlink()  # delete extra fp16 activation TFLite files