Add main entry to package.json

[DucAnhPhi]

• without the main entry, the index file cannot always be found implicitly

[sindresorhus]

without the main entry, the index file cannot always be found implicitly

exports is the modern way to define main entry. This package has the correct config. Any problems are caused by bundlers and other tools.

https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c

[DucAnhPhi]

thanks, good to know