chore: Switch to sha256 from md5 to remedy CodeQL warning (#3356)

This use of md5 doesn't appear to be a cryptographically sensitive
    context, but the easiest remediation for the CodeQL warning is to
    switch to an approved hash function.

sdk/python/jobs/single-step/pytorch/distributed-training-yolov5/yolov5/utils/dataloaders.py

@@ -103,7 +103,7 @@
 def get_hash(paths):
     # Returns a single hash value of a list of paths (files or dirs)
     size = sum(os.path.getsize(p) for p in paths if os.path.exists(p))  # sizes
-    h = hashlib.md5(str(size).encode())  # hash sizes
+    h = hashlib.sha256(str(size).encode())  # hash sizes
     h.update("".join(paths).encode())  # hash paths
     return h.hexdigest()  # return hash