Add support of ntp time verification

Gopkg.lock

@@ -16,6 +16,12 @@
   packages = ["."]
   revision = "2efee857e7cfd4f3d0138cc3cbb1b4966962b93a"
 
+[[projects]]
+  name = "github.com/beevik/ntp"
+  packages = ["."]
+  revision = "62c80a04de2086884d8296004b6d74ee1846c582"
+  version = "v0.2.0"
+
 [[projects]]
   name = "github.com/davecgh/go-spew"
   packages = ["spew"]
@@ -77,6 +83,17 @@
   revision = "eeedf312bc6c57391d84767a4cd413f02a917974"
   version = "v1.8.0"
 
+[[projects]]
+  branch = "master"
+  name = "golang.org/x/net"
+  packages = [
+    "bpf",
+    "internal/iana",
+    "internal/socket",
+    "ipv4"
+  ]
+  revision = "d0887baf81f4598189d4e12a37c6da86f0bba4d0"
+
 [[projects]]
   name = "gopkg.in/alecthomas/kingpin.v2"
   packages = ["."]
@@ -86,6 +103,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "c4fdd3664f683342ad0c2509f4a8bcfe5b267a6e8cdaf36f70d39536bbf89834"
+  inputs-digest = "f828340a30ea13c563829f9a37d0ff62974d4578411c9be02e61125dbdf98692"
   solver-name = "gps-cdcl"
   solver-version = 1