Major Release: Removing babel

Given that nodejs has come a long way and async/await and other modern ES features have long been released, I decided to remove the babel project. Babel was causing more trouble than solving at this point and makes the maintenance of this package difficult.

• feat: upgraded mongoose version to support new mongo connection types d84336d
• feat: .env support d84336d
• feat: remove babel support dcdc96d
• fix: don't throw an error if there are no migrations to run 3ee337c

v3.2.2...v4.0.0