Update subnet sample yaml files to use subnet_secondary_ranges (#1203)

* Replaces 'secondary_ip_range:' with 'secondary_ip_ranges:' in samples

* Replaces 'secondary_ip_range:' with 'secondary_ip_ranges:' in tests/

* reverts previous commit- files in tests/ don't need to be changed

---------

Co-authored-by: Ludovico Magnocavallo <ludomagno@google.com>

fast/stages/2-networking-a-peering/data/subnets/dev/dev-dataplatform-ew1.yaml

@@ -3,6 +3,6 @@
 region: europe-west1
 description: Default subnet for dev Data Platform
 ip_cidr_range: 10.128.48.0/24
-secondary_ip_range:
+secondary_ip_ranges:
    pods: 100.128.48.0/20
    services: 100.255.48.0/24

fast/stages/2-networking-a-peering/data/subnets/dev/dev-gke-nodes-ew1.yaml

@@ -3,6 +3,6 @@
 region: europe-west1
 description: Default subnet for prod gke nodes
 ip_cidr_range: 10.64.0.0/24
-secondary_ip_range:
+secondary_ip_ranges:
    pods: 100.64.0.0/16
    services: 192.168.1.0/24

fast/stages/2-networking-b-vpn/data/subnets/dev/dev-dataplatform-ew1.yaml

@@ -3,6 +3,6 @@
 region: europe-west1
 description: Default subnet for dev Data Platform
 ip_cidr_range: 10.128.48.0/24
-secondary_ip_range:
+secondary_ip_ranges:
    pods: 100.128.48.0/20
    services: 100.255.48.0/24

fast/stages/2-networking-b-vpn/data/subnets/dev/dev-gke-nodes-ew1.yaml

@@ -3,6 +3,6 @@
 region: europe-west1
 description: Default subnet for prod gke nodes
 ip_cidr_range: 10.64.0.0/24
-secondary_ip_range:
+secondary_ip_ranges:
    pods: 100.64.0.0/16
    services: 192.168.1.0/24

fast/stages/2-networking-d-separate-envs/data/subnets/dev/dev-dataplatform-ew1.yaml

@@ -3,6 +3,6 @@
 region: europe-west1
 description: Default subnet for dev Data Platform
 ip_cidr_range: 10.128.48.0/24
-secondary_ip_range:
+secondary_ip_ranges:
    pods: 100.128.48.0/20
    services: 100.255.48.0/24