Add fields to \all endpoint

The API provider is now requiring requests for this endpoint to specify upto 10 fields (https://gitlab.com/restcountries/restcountries/-/issues/265)

Author: modmani

CountriesSwiftUI/Repositories/WebAPI/CountriesWebRepository.swift

@@ -49,7 +49,7 @@ extension RealCountriesWebRepository.API: APICall {
  var path: String {
  switch self {
  case .allCountries:
- return "/all"
+ return "/all?fields=name,translations,population,flag,alpha3Code"
  case let .countryDetails(countryName):
  let encodedName = countryName.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)
  return "/name/\(encodedName ?? countryName)"