Upgrade codeception to avoid abandoned package

[escopecz]

Please be sure you are submitting this against the staging branch.

Q	A
Bug fix?	Y
New feature?	N
Automated tests included?	/
Related user documentation PR URL	/
Related developer documentation PR URL	/
Issues addressed (#s or URLs)	/
BC breaks?	Theoretically yes, but I don't think anyone use the codeception library at the moment.
Deprecations?	N

Description:

Composer reported:

`Package facebook/webdriver is abandoned, you should avoid using it. Use php-webdriver/webdriver instead.

The facebook/webdriver package was dependency of codeception/codeception. The solution I suggest is to upgrade codeception to v4 which doesn't use that dependency. Mautic is prepared for codeception tests but I don't thin any such test exists now so the update should not break anything.

Steps to reproduce the bug:

1. Run composer install and notice the warning.

Steps to test this PR:

1. Repeat the steps, and the warning should be gone.
2. I'd consider passing Travis CI tests as a successful test in this case. It cannot break anything in Mautic itself as it is just a dev dependency.

[anton-vlasenko]

Travis CI doesn't show any errors, no traces of the facebook/webdriver in composer logs so I approve this PR.
Just a small note: composer remove facebook/webdriver command worked for me too.