Bump kubernetes plugin schema version (#3554)

The Kubernetes DNS specification schema version was
updated to 1.1.0 in order to support IPv6
Signed-off-by: Antonio Ojea <antonio.ojea.garcia@gmail.com>

plugin/kubernetes/handler_test.go

@@ -264,7 +264,7 @@ var dnsTestCases = []test.Case{
 		Qname: "dns-version.cluster.local.", Qtype: dns.TypeTXT,
 		Rcode: dns.RcodeSuccess,
 		Answer: []dns.RR{
-			test.TXT("dns-version.cluster.local 28800 IN TXT 1.0.1"),
+			test.TXT("dns-version.cluster.local 28800 IN TXT 1.1.0"),
 		},
 	},
 	// A Service (Headless) does not exist

plugin/kubernetes/kubernetes.go

@@ -69,7 +69,7 @@ const (
 	// podModeInsecure is where pod requests are answered without verifying they exist
 	podModeInsecure = "insecure"
 	// DNSSchemaVersion is the schema version: https://github.com/kubernetes/dns/blob/master/docs/specification.md
-	DNSSchemaVersion = "1.0.1"
+	DNSSchemaVersion = "1.1.0"
 	// Svc is the DNS schema for kubernetes services
 	Svc = "svc"
 	// Pod is the DNS schema for kubernetes pods