TaxProxy calls calculateProductTax wrongly

[Davide]

I'm new with VSF and Shopware, I'm trying to set-up a dev environment.
I've noticed this error from api after shopware data-import to elastic, when i made a product search into the frontend:

vue-storefront-api    |     TypeError: Cannot read property 'tax_class_id' of undefined
vue-storefront-api    |     at Object.calculateProductTax (/var/www/src/lib/taxcalc.js:160:15)
vue-storefront-api    |     at TaxProxy.taxFor (/var/www/src/platform/shopware/tax.js:55:12)
vue-storefront-api    |     at /var/www/src/platform/shopware/tax.js:94:18
vue-storefront-api    |     at process._tickCallback (internal/process/next_tick.js:68:7)

and no items where listed in the results.

looking into vue-storefront-api/src/platform/shopware/tax.js (copied from shopware2vuestorefront/vsf-api-extension/tax.js)

  taxFor (product) {
    return calculateProductTax(product, this._taxClasses, this._taxCountry, this._taxRegion, this._sourcePriceInclTax)
  }

should be

taxFor (product) {
    return calculateProductTax({
      product: product,
      taxClasses: this._taxClasses,
      taxCountry: this._taxCountry,
      taxRegion: this._taxRegion,
      sourcePriceInclTax: this._sourcePriceInclTax
    })
  }

because the taxFor function's parameter is an object:
vue-storefront-api/src/lib/taxcalc.js

export function calculateProductTax ({ product, taxClasses, taxCountry = 'PL', taxRegion = '', sourcePriceInclTax = false, deprecatedPriceFieldsSupport = false, finalPriceInclTax = true, userGroupId = null, isTaxWithUserGroupIsActive }) {

After this change, the product search works.