pyln-client: add missing `min_witness_weight` to fundpsbt/utxopsbt

We need to use it for the 'df_accepter' plugin, so we get the feerate
correct.

Changelog-Added: pyln-client: `fundpsbt`/`utxopsbt` now support `min_witness_weight` param

contrib/pyln-client/pyln/client/lightning.py

@@ -1244,7 +1244,7 @@ class LightningRpc(UnixDomainSocketRpc):
         }
         return self.call("unreserveinputs", payload)
 
-    def fundpsbt(self, satoshi, feerate, startweight, minconf=None, reserve=True, locktime=None):
+    def fundpsbt(self, satoshi, feerate, startweight, minconf=None, reserve=True, locktime=None, min_witness_weight=None):
         """
         Create a PSBT with inputs sufficient to give an output of satoshi.
         """
@@ -1255,10 +1255,11 @@ class LightningRpc(UnixDomainSocketRpc):
             "minconf": minconf,
             "reserve": reserve,
             "locktime": locktime,
+            "min_witness_weight": min_witness_weight,
         }
         return self.call("fundpsbt", payload)
 
-    def utxopsbt(self, satoshi, feerate, startweight, utxos, reserve=True, reservedok=False, locktime=None):
+    def utxopsbt(self, satoshi, feerate, startweight, utxos, reserve=True, reservedok=False, locktime=None, min_witness_weight=None):
         """
         Create a PSBT with given inputs, to give an output of satoshi.
         """
@@ -1270,6 +1271,7 @@ class LightningRpc(UnixDomainSocketRpc):
             "reserve": reserve,
             "reservedok": reservedok,
             "locktime": locktime,
+            "min_witness_weight": min_witness_weight,
         }
         return self.call("utxopsbt", payload)
 

tests/plugins/df_accepter.py

@@ -79,7 +79,8 @@ def on_openchannel(openchannel2, plugin, **kwargs):
     funding = plugin.rpc.fundpsbt(amount,
                                   '{}perkw'.format(feerate),
                                   0, reserve=True,
-                                  locktime=locktime)
+                                  locktime=locktime,
+                                  min_witness_weight=110)
     psbt_obj = psbt_from_base64(funding['psbt'])
 
     excess = Millisatoshi(funding['excess_msat'])