lnwire: add FirstBlock and BlockRange to GossipTimestampRange

Add new FirstBlockHeight and BlockRange TLV fields to the
GossipTimestampRange message. This will be used to query for Gossip 1.75
messages which are timestamped using block height instead of Unix
timestamps.

lnwire/lnwire_test.go

@@ -1215,6 +1215,35 @@ func TestLightningWireProtocol(t *testing.T) {
 
 			v[0] = reflect.ValueOf(req)
 		},
+		MsgGossipTimestampRange: func(v []reflect.Value, r *rand.Rand) {
+			req := GossipTimestampRange{
+				FirstTimestamp: rand.Uint32(),
+				TimestampRange: rand.Uint32(),
+				ExtraData:      make([]byte, 0),
+			}
+
+			_, err := rand.Read(req.ChainHash[:])
+			require.NoError(t, err)
+
+			// Sometimes add a block range.
+			if r.Int31()%2 == 0 {
+				firstBlock := tlv.ZeroRecordT[
+					tlv.TlvType2, uint32,
+				]()
+				firstBlock.Val = rand.Uint32()
+				req.FirstBlockHeight = tlv.SomeRecordT(
+					firstBlock,
+				)
+
+				blockRange := tlv.ZeroRecordT[
+					tlv.TlvType4, uint32,
+				]()
+				blockRange.Val = rand.Uint32()
+				req.BlockRange = tlv.SomeRecordT(blockRange)
+			}
+
+			v[0] = reflect.ValueOf(req)
+		},
 		MsgQueryShortChanIDs: func(v []reflect.Value, r *rand.Rand) {
 			req := QueryShortChanIDs{
 				ExtraData: make([]byte, 0),