Symfony 4 support

[walterdolce]

So the time has come to upgrade an old Silex app to Symfony 4 and this app uses your lovely extension. However, it looks like there's currently no support for Symfony 4 😢

 Problem 2
    - Installation request for ciaranmcnulty/behat-localwebserverextension 1.1.3 -> satisfiable by ciaranmcnulty/behat-localwebserverextension[1.1.3].
    - ciaranmcnulty/behat-localwebserverextension 1.1.3 requires symfony/process ~2.3||~3.0 -> no matching package found.

Is ~3.0 a strict requirement or could that be bumped to ~4.0?

[ciaranmcnulty]

I doubt there’s any breaks. Make a PR?

[walterdolce]

Of course! Will make one ASAP

[walterdolce]

Done: #8

[walterdolce]

Polite nugde :) @ciaranmcnulty