Retry `check_requirements` once on failure (#9466)

ultralytics/utils/checks.py

@@ -28,6 +28,7 @@ from ultralytics.utils import (
     ONLINE,
     ROOT,
     USER_CONFIG_DIR,
+    Retry,
     SimpleNamespace,
     ThreadingLocked,
     TryExcept,
@@ -390,6 +391,7 @@ def check_requirements(requirements=ROOT.parent / "requirements.txt", exclude=()
             try:
                 t = time.time()
                 assert is_online(), "AutoUpdate skipped (offline)"
+                with Retry(times=1, delay=1):  # retry once on failure after 1 second
                     LOGGER.info(subprocess.check_output(f"pip install --no-cache {s} {cmds}", shell=True).decode())
                 dt = time.time() - t
                 LOGGER.info(