Add Lookup API support

[ppai-plivo]

Sample program:

<?php
require 'vendor/autoload.php';
use Plivo\RestClient;
 
$client = new RestClient("XXXX", "XXXX");

try {
    $response = $client->lookup->get("+14154305555", "carrier");
    var_dump($response);
} catch (PlivoRestException $ex) {
    print_r(ex);
}

array(6) {
  ["api_id"]=>
  string(36) "f7e4956f-7ab6-4f27-9e95-4c96b2ec4325"
  ["phone_number"]=>
  string(12) "+14154305555"
  ["country"]=>
  array(3) {
    ["name"]=>
    string(13) "United States"
    ["code_iso2"]=>
    string(2) "US"
    ["code_iso3"]=>
    string(3) "USA"
  }
  ["format"]=>
  array(4) {
    ["e164"]=>
    string(12) "+14154305555"
    ["national"]=>
    string(14) "(415) 430-5555"
    ["international"]=>
    string(15) "+1 415-430-5555"
    ["rfc3966"]=>
    string(19) "tel:+1-415-430-5555"
  }
  ["carrier"]=>
  array(5) {
    ["mobile_country_code"]=>
    string(3) "310"
    ["mobile_network_code"]=>
    string(3) "150"
    ["name"]=>
    string(17) "Cingular Wireless"
    ["type"]=>
    string(6) "mobile"
    ["ported"]=>
    bool(true)
  }
  ["resource_uri"]=>
  string(43) "/v1/Lookup/Number/+14154305555?type=carrier"
}

[ppai-plivo]

Unit test:

$ ./vendor/bin/phpunit --debug tests/Resources/LookupTest.php
PHPUnit 8.5.8 by Sebastian Bergmann and contributors.

Test 'Plivo\Tests\Resources\LookupTest::testLookupGet' started
Test 'Plivo\Tests\Resources\LookupTest::testLookupGet' ended


Time: 30 ms, Memory: 4.00 MB

OK (1 test, 3 assertions)