[BREAKING CHANGE] Remove default value for PC version. Now the user must specify the PC version to use.

 From developer perspective, this means that we do not need to do a new release of PCUI only to bumo the default PC version.

Author: gmarciani

infrastructure/parallelcluster-ui.yaml

@@ -32,9 +32,8 @@ Parameters:
     Type: String
     Default: ''
   Version:
-    Description: Version of AWS ParallelCluster to deploy
+    Description: Version of AWS ParallelCluster to deploy.
     Type: String
-    Default: 3.11.1
   ImageBuilderVpcId:
     Description: (Optional) Select the VPC to use for building the container images. If not selected, default VPC will be used.
     Type: String