Set transformers==5.8.1

Signed-off-by: Charlie Truong <chtruong@nvidia.com>

Author: chtruong814

pyproject.toml

@@ -159,7 +159,7 @@ override-dependencies = [
     "transformer-engine-cu13>=2.16.0a0,<2.19.0; sys_platform != 'darwin'",
     "transformer-engine-cu12; sys_platform == 'never'",
     "mamba-ssm>=2.3.0,<2.4.0",
-    "transformers>=5.0.0",
+    "transformers==5.8.1",
     "protobuf~=6.33.5",
     "opencv-python-headless; sys_platform == 'never'",
     "cryptography>=43.0.0,<47",