Added nextflow upgrade cmd

Author: narendran1560

cft-templates/nextflow-advanced.yaml

@@ -542,7 +542,11 @@ Resources:
       UserData:
         Fn::Base64: !Sub |
           #!/bin/bash -xe
+          exec > >(tee /var/log/user-data.log|logger -t user-data -s 2>/dev/console) 2>&1
 
+          cd /usr/bin
+          curl -s https://get.nextflow.io | bash
+
           sudo yum update -y --security
           cd /root/