Fix: Change relevance to double on peers info dto

[bhaan]

I got an exception calling subscribeTorrentPeersData on the SyncController. The client has the PeerInfo.relevance datatype as an int?, but the API appears to be sending a double. While the documentation doesn't appear to have any information for this response object, I see that the WebUI renders the "relevance" column in the "peers" tab as a percent, suggesting that the API is responding with a value between 0 and 1.

This change updates the datatype to be double? rather than int?.

This is the stacktrace I received:

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: type 'double' is not a subtype of type 'int?' in type cast
#0      _$PeersInfoFromJson (package:qbittorrent_api/src/v2/sync/dto/peers_info.g.dart:23:36)
#1      new PeersInfo.fromJson (package:qbittorrent_api/src/v2/sync/dto/peers_info.dart:27:7)
#2      _$PeersDataFromJson.<anonymous closure> (package:qbittorrent_api/src/v2/sync/dto/peers_data.g.dart:12:41)
...

[yosemiteyss]

thx!