update nixpkgs{,-unstable}

btcpayserver: 1.3.7 -> 1.4.4
electrs: 0.9.4 -> 0.9.5
lnd: 0.14.1-beta -> 0.14.2-beta
nbxplorer: 2.2.18 -> 2.2.20

Author: jonasnick

flake.lock

@@ -193,7 +193,7 @@ def _():
     wait_for_open_port(ip("nbxplorer"), 24444)
 
     assert_running("btcpayserver")
-    machine.wait_until_succeeds(log_has_string("btcpayserver", "Listening on"))
+    machine.wait_until_succeeds(log_has_string("btcpayserver", "Now listening on"))
     wait_for_open_port(ip("btcpayserver"), 23000)
     # test lnd custom macaroon
     assert_matches(