Update Caddy to 1.0.1, and update import path (#2961)

* Update Caddy to 1.0.1, and update import path

This fix updates caddy to 1.0.1 and also
updates the import path to github.com/caddyserver/caddy

This fix fixes 2959

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Also update plugin.cfg

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Update and bump zplugin.go

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

plugin/metrics/register.go

@@ -3,7 +3,7 @@ package metrics
 import (
 	"github.com/coredns/coredns/core/dnsserver"
 
-	"github.com/mholt/caddy"
+	"github.com/caddyserver/caddy"
 	"github.com/prometheus/client_golang/prometheus"
 )
 

plugin/metrics/setup.go

@@ -11,7 +11,7 @@ import (
 	clog "github.com/coredns/coredns/plugin/pkg/log"
 	"github.com/coredns/coredns/plugin/pkg/uniq"
 
-	"github.com/mholt/caddy"
+	"github.com/caddyserver/caddy"
 )
 
 var (

plugin/metrics/setup_test.go

@@ -3,7 +3,7 @@ package metrics
 import (
 	"testing"
 
-	"github.com/mholt/caddy"
+	"github.com/caddyserver/caddy"
 )
 
 func TestPrometheusParse(t *testing.T) {