taprpc: add groupkey to AddInvoice

Author: GeorgeTsagk

taprpc/tapchannelrpc/tapchannel.pb.go

@@ -192,6 +192,11 @@ message AddInvoiceRequest {
     // won't be settled automatically. Instead, users will need to use the
     // invoicesrpc.SettleInvoice call to manually settle the invoice.
     HodlInvoice hodl_invoice = 5;
+
+    // The group key which dictates which assets may be accepted for this
+    // invoice. If set, any asset that belongs to this group may be accepted to
+    // settle this invoice. Mutually exclusive to asset_id.
+    bytes group_key = 6;
 }
 
 message AddInvoiceResponse {

taprpc/tapchannelrpc/tapchannel.proto

@@ -1512,6 +1512,11 @@
         "hodl_invoice": {
           "$ref": "#/definitions/tapchannelrpcHodlInvoice",
           "description": "If set, then this will make the invoice created a hodl invoice, which\nwon't be settled automatically. Instead, users will need to use the\ninvoicesrpc.SettleInvoice call to manually settle the invoice."
+        },
+        "group_key": {
+          "type": "string",
+          "format": "byte",
+          "description": "The group key which dictates which assets may be accepted for this\ninvoice. If set, any asset that belongs to this group may be accepted to\nsettle this invoice. Mutually exclusive to asset_id."
         }
       }
     },