Add package.json "type" field

[julienchazal]

This change makes Glide compatible with Node > 15

Within a package, the package.json "type" field defines how Node.js should interpret .js files. If a package.json file does not have a "type" field, .js files are treated as CommonJS.

A package.json "type" value of "module" tells Node.js to interpret .js files within that package as using ES module syntax.

[julienchazal]

see #620

[jedrzejchalubek]

Looks like the build is failing as adding this property requires to use of ESM export/import module syntax. Probably jest.config.js just need to use export default instead of module.exports =

[julienchazal]

thanks @jedrzejchalubek 👍