use go 1.12

Signed-off-by: hongming <talonwan@yunify.com>

vendor/github.com/miekg/dns/version.go

@@ -0,0 +1,15 @@
+package dns
+
+import "fmt"
+
+// Version is current version of this library.
+var Version = V{1, 1, 6}
+
+// V holds the version of this library.
+type V struct {
+	Major, Minor, Patch int
+}
+
+func (v V) String() string {
+	return fmt.Sprintf("%d.%d.%d", v.Major, v.Minor, v.Patch)
+}