fix passing in python3 as command

Author: shreyapandit

tests/integ/test_processing.py

@@ -162,6 +162,7 @@ def test_sklearn_with_customizations(
     sklearn_processor = SKLearnProcessor(
         framework_version=sklearn_latest_version,
         role=ROLE,
+        command=["python3"],
         instance_type=cpu_instance_type,
         instance_count=1,
         volume_size_in_gb=100,
@@ -288,6 +289,9 @@ def test_sklearn_with_custom_default_bucket(
     assert job_description["ProcessingInputs"][0]["InputName"] == "dummy_input"
     assert custom_bucket_name in job_description["ProcessingInputs"][0]["S3Input"]["S3Uri"]
 
+    assert job_description["ProcessingInputs"][2]["InputName"] == "entrypoint"
+    assert custom_bucket_name in job_description["ProcessingInputs"][2]["S3Input"]["S3Uri"]
+
     assert job_description["ProcessingJobName"].startswith("test-sklearn-with-customizations")
 
     assert job_description["ProcessingJobStatus"] == "Completed"