lnrpc: add no_publish flag to PSBT shim

lnrpc/rpc.proto

@@ -1768,6 +1768,16 @@ message PsbtShim {
     non-empty, it must be a binary serialized PSBT.
     */
     bytes base_psbt = 2;
+
+    /*
+    If a channel should be part of a batch (multiple channel openings in one
+    transaction), it can be dangerous if the whole batch transaction is
+    published too early before all channel opening negotiations are completed.
+    This flag prevents this particular channel from broadcasting the transaction
+    after the negotiation with the remote peer. In a batch of channel openings
+    this flag should be set to true for every channel but the very last.
+    */
+    bool no_publish = 3;
 }
 
 message FundingShim {

lnrpc/rpc.swagger.json

@@ -4816,6 +4816,11 @@
           "type": "string",
           "format": "byte",
           "description": "An optional base PSBT the new channel output will be added to. If this is\nnon-empty, it must be a binary serialized PSBT."
+        },
+        "no_publish": {
+          "type": "boolean",
+          "format": "boolean",
+          "description": "If a channel should be part of a batch (multiple channel openings in one\ntransaction), it can be dangerous if the whole batch transaction is\npublished too early before all channel opening negotiations are completed.\nThis flag prevents this particular channel from broadcasting the transaction\nafter the negotiation with the remote peer. In a batch of channel openings\nthis flag should be set to true for every channel but the very last."
         }
       }
     },