v0.6.0
bump version to 0.6.0 (#563) Key changes: Feature: data channel pool: https://github.com/RingsNetwork/rings/pull/562 Feature: Using callback instead MPMC channel: https://github.com/RingsNetwork/rings/pull/561 Chore: Make rings-snark optional: https://github.com/RingsNetwork/rings/pull/558 Chore: Using forked protocolJs: https://github.com/RingsNetwork/rings/pull/556