Update replace statement in go.mod: (#3157)

```
replace github.com/miekg/dns v1.1.3 => github.com/miekg/dns v1.1.16
```

so that we only end up with one version of github.com/miekg/dns
(caddy still use 1.1.3)
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/Azure/go-autorest/autorest/azure/auth v0.3.0
 	github.com/Azure/go-autorest/autorest/to v0.2.0 // indirect
 	github.com/Shopify/sarama v1.21.0 // indirect
+	github.com/apache/thrift v0.12.0 // indirect
 	github.com/aws/aws-sdk-go v1.23.3
 	github.com/caddyserver/caddy v1.0.3
 	github.com/coredns/federation v0.0.0-20190818181423-e032b096babe
@@ -73,4 +74,4 @@ require (
 	sigs.k8s.io/yaml v1.1.0 // indirect
 )
 
-replace github.com/miekg/dns v1.1.3 => github.com/miekg/dns v1.1.15
+replace github.com/miekg/dns v1.1.3 => github.com/miekg/dns v1.1.16

go.sum

@@ -178,6 +178,7 @@ github.com/google/pprof v0.0.0-20190515194954-54271f7e092f/go.mod h1:zfwlbNMJ+OI
 github.com/google/uuid v1.1.1 h1:Gkbcsh/GbpXz7lPftLA3P6TYMwjCLYm83jiFQZF/3gY=
 github.com/google/uuid v1.1.1/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/googleapis/gax-go/v2 v2.0.4/go.mod h1:0Wqv26UfaUD9n4G6kQubkQ+KchISgw+vpHVxEJEs9eg=
+github.com/googleapis/gax-go/v2 v2.0.5 h1:sjZBwGj9Jlw33ImPtvFviGYvseOtDM7hkSKB7+Tv3SM=
 github.com/googleapis/gax-go/v2 v2.0.5/go.mod h1:DWXyrwAJ9X0FpwwEdw+IPEYBICEFu5mhpdKc/us6bOk=
 github.com/googleapis/gnostic v0.2.0 h1:l6N3VoaVzTncYYW+9yOz2LJJammFZGBO13sqgEhpy9g=
 github.com/googleapis/gnostic v0.2.0/go.mod h1:sJBsCZ4ayReDTBIg8b9dl28c5xFWyhBTVRp3pOg5EKY=