Simplify check_requirements() usage (#4855)

* Simplify `check_requirements()` usage

* remove assert, print()

utils/general.py

@@ -37,6 +37,9 @@ pd.options.display.max_columns = 10
 cv2.setNumThreads(0)  # prevent OpenCV from multithreading (incompatible with PyTorch DataLoader)
 os.environ['NUMEXPR_MAX_THREADS'] = str(min(os.cpu_count(), 8))  # NumExpr max threads
 
+FILE = Path(__file__).resolve()
+ROOT = FILE.parents[1]  # YOLOv5 root directory
+
 
 class Profile(contextlib.ContextDecorator):
     # Usage: @Profile() decorator or 'with Profile():' context manager
@@ -222,7 +225,7 @@ def check_version(current='0.0.0', minimum='0.0.0', name='version ', pinned=Fals
 
 
 @try_except
-def check_requirements(requirements='requirements.txt', exclude=(), install=True):
+def check_requirements(requirements=ROOT / 'requirements.txt', exclude=(), install=True):
     # Check installed dependencies meet requirements (pass *.txt file or list of packages)
     prefix = colorstr('red', 'bold', 'requirements:')
     check_python()  # check python version