Avoid backup cache crash

[tleyden]

Fix for #2

Lmk if this looks good, I still need to clean up formatting (4 space vs 2 space indent)

[david9472]

I had the same issue and implemented a similar fix (see below). Tested your changes -> LGTM

  func backupCache() {
    queue.sync(flags: .barrier) {
      do {
        let encoder = JSONEncoder()
        let dateFormatter = ISO8601DateFormatter()
        dateFormatter.formatOptions = [.withInternetDateTime]

        encoder.dateEncodingStrategy = .custom { date, encoder in
            var container = encoder.singleValueContainer()
            try container.encode(dateFormatter.string(from: date))
        }

        let data = try encoder.encode(cachedLogs)

        try data.write(to: LogsCache.fileURL())
        self.cachedLogs = []
      } catch {
        if isDebug {
          print("Error saving Logs cache.")
        }
      }
    }
  }