[RFC] Fix abandoned packages on composer install/update

[bytehead]

Package guzzle/guzzle is abandoned, you should avoid using it. Use guzzlehttp/guzzle instead.
Package satooshi/php-coveralls is abandoned, you should avoid using it. Use php-coveralls/php-coveralls instead.

Don't know if we can use php-coveralls/php-coveralls in version 2.x.

[leofeyer]

Thank you @bytehead.