chore: upgrade connext to 6.6.2

[ghost]

No description provided.

[raladev]

• got SendPaymentFailure for ETH/BTC pair, but swaps work in most cases.

Steps(from maker side):
1.sell 300 XUC/DAI 2 1 -> success
2.buy 300 XUC/USDT mkt (taker placed order, maker fills) -> success
3.buy 1 ETH/BTC 0.1 1 -> SendPaymentFailure
4. sell 1 ETH/BTC 0.1 1 -> success
5. buy 1 ETH/BTC 0.1 1 -> success
6. buy 100 XUC/BTC 0.01 1 -> success

1.Logs of maker's connext node contain 'invalid response - 0' err;
2. In my opinion connext node writes to much in log file (217 msgs per sec).
Logs:
invalid_btc_taker.log
invalid_connext_taker.log
invalid_xud_taker.log

invalid_btc_maker.log
invalid_connext_maker.log
invalid_xud_maker.log