Add support for Pakistan 326 code (update metadata)

[aikikode]

Current version of the library does not support [Pakistan (PK) code 326]:
The code

package main

import (
    "fmt"
    libphonenumber "github.com/nyaruka/phonenumbers"
)

func main() {
    parsedPhoneNumber, _ := libphonenumber.Parse("0325-0000000", "PK")
    fmt.Println(parsedPhoneNumber, libphonenumber.IsValidNumber(parsedPhoneNumber))
    parsedPhoneNumber, _ = libphonenumber.Parse("0326-0000000", "PK")
    fmt.Println(parsedPhoneNumber, libphonenumber.IsValidNumber(parsedPhoneNumber))
}

Provides:

country_code:92 national_number:3250000000  true
country_code:92 national_number:3260000000  false   // should be true

(https://en.wikipedia.org/wiki/Telephone_numbers_in_Pakistan) - only the codes from 320 to 325 according to PhoneMetadata.GetMobile() being:

national_number_pattern:"3(?:[014]\\d|2[0-5]|3[0-7]|55|64)\\d{7}" possible_length:10 example_number:"3012345678"

Looks like the metadata is outdated from the official Google library, e.g. see the query for the same phone number "0326-0000000" with sample google service where IsValidNumber(): true: https://rawgit.com/googlei18n/libphonenumber/master/javascript/i18n/phonenumbers/demo-compiled.html

and current library: https://phonenumbers.temba.io/ where is_valid: false

[aikikode]

Hi @rowanseymour, I see you already merged #111 to add this support, thank you! Do you plan to do a new release/tag for this library with this change?

[aikikode]

Resolved by #111 (v1.0.75)