deps: Require ext-openssl

[tienvx]

• Look like ext-openssl is required in <= v8 because we call file_get_contents with https scheme 50140a5

      $uri  = "https://github.com/pact-foundation/pact-ruby-standalone/releases/download/v1.29.2/{$fileName}";
      $data = \file_get_contents($uri);

• v9 + v10 use composer to download files with https scheme. Composer will "require" ext-openssl for us, by throwing an exception if it's not available https://github.com/composer/composer/blob/main/src/Composer/Downloader/FileDownloader.php#L468-L470

      if (!extension_loaded('openssl') && 0 === strpos($url, 'https:')) {
          throw new \RuntimeException('You must enable the openssl extension to download files via https');
      }

• I think not requiring ext-openssl is not wrong. But requiring ext-openssl is also fine. So I added it again.
• openssl extension is bundled into PHP, and I can't disable it to test
  • On mac/linux: Could not disable openssl on PHP 8.3.3 as it not a shared extension
  • On windows: Can disable, but can't verify that composer install will throw exception, because of this error The composer.json file at './composer.json' does not validate; run 'composer validate' to check for errors https://github.com/tienvx/pact-php/actions/runs/8277789711/job/22648837639

[Lewiscowles1986]

Thank you. Relying on internals of a third party system vs explicitly calling out needs ftw.