Fix type of public_net_allocation_pools

https://review.opendev.org/#/c/733598/ added support
of allocation_pools, but set type of public_net_allocation_pools
to comma_delimited_list which causes below issue because for
comma_delimited_list, list items are converted to string:-

Property error: : resources.public_subnet.properties.allocation_pools[0]:
"{'end': '10.0.0.199', 'start': '10.0.0.128'}" is not a map

We need to use type: json to get it work, this patch fixes it.

Related-Bug: #1874418
Change-Id: Iaebb297e5018ce8db6dd1f67a308e7707117fe03

environments/base.yaml

@@ -62,7 +62,7 @@ parameter_defaults:
   public_net: public
 
   # Allocation Pools for the public network
-  # Type: comma_delimited_list
+  # Type: json
   public_net_allocation_pools: []
 
   # CIDR for external network subnet

templates/undercloud-networks-existing.yaml

@@ -32,7 +32,7 @@ parameters:
     default: 10.0.0.0/24
 
   public_net_allocation_pools:
-    type: comma_delimited_list
+    type: json
     description: Allocation Pools for the public network
     default: []
 

templates/undercloud-networks-public-router.yaml

@@ -32,7 +32,7 @@ parameters:
     default: 10.0.0.0/24
 
   public_net_allocation_pools:
-    type: comma_delimited_list
+    type: json
     description: Allocation Pools for the public network
     default: []
 

templates/undercloud-networks-routed.yaml

@@ -87,7 +87,7 @@ parameters:
     default: 10.0.0.0/24
 
   public_net_allocation_pools:
-    type: comma_delimited_list
+    type: json
     description: Allocation Pools for the public network
     default: []
 

templates/undercloud-networks.yaml

@@ -32,7 +32,7 @@ parameters:
     default: 10.0.0.0/24
 
   public_net_allocation_pools:
-    type: comma_delimited_list
+    type: json
     description: Allocation Pools for the public network
     default: []