* Updating nim-libp2p to fix the `wss` connectivity issue
* The `nim-libp2p` adds many changes although we are actually interested
in the latest commit:
> wstransport.nim: avoid re-raising 'TransportOsError' to avoid stopping
`switch.accept` (#929)
* The `nim-stew` bump is needed so that the `nim-libp2p` can compile.
* The changes in `waku_node.nim` are needed due to the changes in
`nim-stew`.
* waku_node.nim: returning a "completed" future within 'statusAndConfidenceHandler'
This is aimed to avoid the next exception happening in the wakunode:
```
Unhandled defect: Async procedure (service.nim(74) callHandler)
yielded `nil`, are you await'ing a `nil` Future? [AssertionDefect]
```
* Adding 'async' to 'statusAndConfidenceHandler' so that it properly returns a Future[void]