Fix misplaced parenthesis for taxClasses.find

[DylannCordel]

(and also avoid a ParseInt call for each item tested)

[pkarw]

Wow, good one :) Please update changelog

[andrzejewsky]

@DylannCordel just changed base for you - please only update changelog as @pkarw and we can merge it.

[DylannCordel]

Thx @andrzejewsky and @pkarw
Changelog has been updated. Same fix on the API has been merged into master branch. If calculateServerSide is set to True, same bug will still be there until people update the API once it will be released. To avoid that without changing the API source code, a trick is to filter tax rules before the calculateProductTax call. It can been done in the <platform>.taxFor method. eg:

  taxFor (product) {
    let product_tax_class_id = parseInt(product.tax_class_id)
    let productTaxRules = this._taxClasses.filter(
      (taxRule) => taxRule.product_tax_class_ids.indexOf(product_tax_class_id) > -1
    );
    // we DO NOT use `this._taxClasses` because `calculateProductTax` is currently bugged.
    // we MUST pre-filter tax rules to only keep matching rules for the current product.
    return calculateProductTax(product, productTaxRules, this._taxCountry, this._taxRegion, this._sourcePriceInclTax)
  }

I let this here if it can be usefull for someone.