Typescript ES6 support

[victors1682]

Describe the feature you'd like
I attempted to iterate through a map using ES6 syntax but had to resort to the older approach. Not urgent but nice to have.

error TS2802: Type 'Map<any, any>' can only be iterated through when using the '--downlevelIteration' flag or with a '--target' of 'es2015' or higher.

     for (let [key, values] of variantMap) {

faststore/packages/core/tsconfig.json

Line 23 in 271888c

"target": "es5",

[gvc]

Thank you for the feedback. The team will look into this 🚀