Serverless MySQL: v1.5.2 released

Minor bug fix and security patch

Added a retry for another error that is resetting connections (this should fix the issues in #57 and #62) as well as some minor documentation and dependency updates.

Full Release Notes: https://github.com/jeremydaly/serverless-mysql/releases/tag/v1.5.2

NPM: https://www.npmjs.com/package/serverless-mysql

GitHub: https://github.com/jeremydaly/serverless-mysql