fix(discovery): allow FindPeers limit to be 0

[guillaumemichel]

go-libp2p/p2p/discovery/routing/routing.go

Lines 58 to 76 in cb81b3e

	func (d *RoutingDiscovery) FindPeers(ctx context.Context, ns string, opts ...discovery.Option) (<-chan peer.AddrInfo, error) {
	var options discovery.Options
	err := options.Apply(opts...)
	if err != nil {
	return nil, err
	}
	limit := options.Limit
	if limit == 0 {
	limit = 100 // that's just arbitrary, but FindProvidersAsync needs a count
	}
	cid, err := nsToCid(ns)
	if err != nil {
	return nil, err
	}
	return d.FindProvidersAsync(ctx, cid, limit), nil
	}

FindProvidersAsync allows a limit of 0 to return all found providers. However, it is impossible to make use of this feature with FindPeers since it sets the limit to 100 if it was previously 0.

This is a non breaking fix, users omitting the Limit(X) parameter will continue to have (at most) 100 results returned. Alternatively, we could change the default to return all found peers.

resolves #2859