fix: use us-west-2 endpoint for sts in buildspec (#1083)

Author: Dan

buildspec.yml

@@ -25,7 +25,7 @@ phases:
       - |
         if [ -d "ci-lock" ]; then
           FILENAME=$(ls ci-lock/ || true)
-          ACCOUNT=$(aws sts get-caller-identity --output text | awk '{print $1}')
+          ACCOUNT=$(aws sts get-caller-identity --region us-west-2 --output text | awk '{print $1}')
           S3_BUCKET_DIR=s3://sagemaker-us-west-2-${ACCOUNT}/ci-lock/
           aws s3 rm ${S3_BUCKET_DIR}${FILENAME}
         fi