Update env_logger requirement from 0.3.3 to 0.6.1
Update env_logger requirement from 0.3.3 to 0.6.1

Updates the requirements on [env_logger](https://github.com/sebasmagri/env_logger) to permit the latest version.
- [Release notes](https://github.com/sebasmagri/env_logger/releases)
- [Changelog](https://github.com/sebasmagri/env_logger/blob/master/CHANGELOG.md)
- [Commits](https://github.com/sebasmagri/env_logger/commits/v0.6.1)
cstorey/phi-accrual-rs