lnrpc+rpcserver: Adding last_update timestamp to RoutingPolicy

lnrpc/rpc.proto: updates RoutingPolicy last_update number

rpcserver: adding LastUpdate field to marshalDbEdge

This commit adds a LastUpdate field to each RoutingPolicy, it will show
the time each RoutingPolicy was updated.

lnrpc: regenerating proto files

lnrpc/rpc.proto

@@ -1794,6 +1794,7 @@ message RoutingPolicy {
     int64 fee_rate_milli_msat = 4 [json_name = "fee_rate_milli_msat"];
     bool disabled = 5 [json_name = "disabled"];
     uint64 max_htlc_msat = 6 [json_name = "max_htlc_msat"];
+    uint32 last_update = 7 [json_name = "last_update"];
 }
 
 /**
@@ -1813,7 +1814,7 @@ message ChannelEdge {
     uint64 channel_id = 1 [json_name = "channel_id"];
     string chan_point = 2 [json_name = "chan_point"];
 
-    uint32 last_update = 3 [json_name = "last_update"];
+    uint32 last_update = 3 [json_name = "last_update", deprecated = true];
 
     string node1_pub = 4 [json_name = "node1_pub"];
     string node2_pub = 5 [json_name = "node2_pub"];

lnrpc/rpc.swagger.json

@@ -3166,6 +3166,10 @@
         "max_htlc_msat": {
           "type": "string",
           "format": "uint64"
+        },
+        "last_update": {
+          "type": "integer",
+          "format": "int64"
         }
       }
     },