0.5.8-beta1

What's Changed

• iOS performance by @nplasterer in #59
• Bump to latest libxmtp for max epoch work by @nplasterer in #60
• Performance improvements and revokation by @nplasterer in #61
• Possible group fork fixes, sync all group improvements by @cameronvoell in #62

Full Changelog: 0.5.7-beta2...0.5.8-beta1