clock: add go.mod

clock/go.mod

@@ -0,0 +1,3 @@
+module github.com/lightningnetwork/lnd/clock
+
+go 1.13

go.mod

@@ -48,6 +48,7 @@ require (
 	github.com/lightninglabs/protobuf-hex-display v1.3.3-0.20191212020323-b444784ce75d
 	github.com/lightningnetwork/lightning-onion v1.0.2-0.20200501022730-3c8c8d0b89ea
 	github.com/lightningnetwork/lnd/cert v1.0.2
+	github.com/lightningnetwork/lnd/clock v1.0.0
 	github.com/lightningnetwork/lnd/queue v1.0.4
 	github.com/lightningnetwork/lnd/ticker v1.0.0
 	github.com/ltcsuite/ltcd v0.0.0-20190101042124-f37f8bf35796
@@ -82,6 +83,8 @@ replace github.com/lightningnetwork/lnd/queue => ./queue
 
 replace github.com/lightningnetwork/lnd/cert => ./cert
 
+replace github.com/lightningnetwork/lnd/clock => ./clock
+
 replace git.schwanenlied.me/yawning/bsaes.git => github.com/Yawning/bsaes v0.0.0-20180720073208-c0276d75487e
 
 // Pin this version that we know works explicitly, even though the