Consider updating PHPSpec package

[Chun-Sheng, Li]

As title, it will be failed on php-7.4 version when phpspec is ^5.0 version.

The related issue is available here.

And it should be good for php-7.4 version uses phpspec ^6.0 version.

To resolve this issue, I think we have two different ways:

• Defining two phpspec version with ^5.0 || ^6.0 inside require block on composer.json.
  And using the composer update --prefer-dist --no-interaction during Travis CI build.
• Removing composer.lock and define two phpspec version with ^5.0 || ^6.0 inside require block on composer.json.

[Thomas Galvaing]

Hello @peter279k,

Thanks for your suggestion. We just tagged a new version of our client with PHP 7.4 and PHPSpec 7.1.
see c43fdd4

Regards,

[Chun-Sheng, Li]

Thanks. And it will be resolved now :).