routing/router: when applying onion failure channel update, set max htlc

In this commit, we ensure that when we update an edge
as a result of a ChannelUpdate being returned from an
onion failure, the max htlc portion of the channel update
is included in the edge update.

routing/router.go

@@ -2079,6 +2079,7 @@ func (r *ChannelRouter) applyChannelUpdate(msg *lnwire.ChannelUpdate,
 		ChannelFlags:              msg.ChannelFlags,
 		TimeLockDelta:             msg.TimeLockDelta,
 		MinHTLC:                   msg.HtlcMinimumMsat,
+		MaxHTLC:                   msg.HtlcMaximumMsat,
 		FeeBaseMSat:               lnwire.MilliSatoshi(msg.BaseFee),
 		FeeProportionalMillionths: lnwire.MilliSatoshi(msg.FeeRate),
 	})