Pin NLTK version to fix JAX ci (#1096)

Signed-off-by: Kirthi Shankar Sivamani <ksivamani@nvidia.com>
Co-authored-by: Phuong Nguyen <36155692+phu0ngng@users.noreply.github.com>

qa/L0_jax_unittest/test.sh

@@ -4,6 +4,7 @@
 
 set -xe
 
+pip install nltk==3.8.1
 pip install pytest==8.2.1
 : ${TE_PATH:=/opt/transformerengine}