Update sagemaker-python-sdk in test env (#317)

Co-authored-by: SK <saravsak@amazon.com>

Author: saravsak

setup.py

@@ -30,7 +30,7 @@ def read_version():
 
 
 test_dependencies = ['tox', 'flake8', 'pytest', 'pytest-cov', 'pytest-xdist', 'mock',
-                     'sagemaker==1.50.1', 'tensorflow<2.0', 'docker-compose', 'boto3==1.10.50',
+                     'sagemaker==1.51.3', 'tensorflow<2.0', 'docker-compose', 'boto3==1.10.50',
                      'six==1.13.0', 'python-dateutil>=2.1,<2.8.1', 'botocore==1.13.50',
                      'requests-mock', 'awscli==1.16.314']