add DeletionPolicy Retain to DNS zones

this can easily create a conflict if you start manually adding records to the zone

Author: tj

platform/lambda/stack/resources/resources.go

@@ -109,7 +109,8 @@ func dnsZone(c *Config, m Map, domain string) interface{} {
 
 	// new zone
 	m[id] = Map{
-		"Type": "AWS::Route53::HostedZone",
+		"Type":           "AWS::Route53::HostedZone",
+		"DeletionPolicy": "Retain",
 		"Properties": Map{
 			"Name": domain,
 		},

platform/lambda/stack/resources/resources_test.go

@@ -458,6 +458,7 @@ func Example_stageDNSZone() {
 	dump(c, "DnsZoneUpExampleCom")
 	// Output:
 	// {
+	//   "DeletionPolicy": "Retain",
 	//   "Properties": {
 	//     "Name": "up-example.com"
 	//   },
@@ -522,6 +523,7 @@ func Example_dnsZone() {
 	dump(c, "DnsZoneUpExampleCom")
 	// Output:
 	// {
+	//   "DeletionPolicy": "Retain",
 	//   "Properties": {
 	//     "Name": "up-example.com"
 	//   },