Update dependencies

[schmengler]

Currently, solr-base ^3.0.0 is required, it should be ^3.2.2

Wercker still runs on PHP 5.5, should be updated to PHP 5.6. We want to keep PHP 5.6 compatibility for the Magento 1 module, but testing with PHP 5.5 should be dropped.

The current combination results in CI failures because 3.2.0-alpha actually needs PHP 7, a requirement that has been dropped later, together with an explicit dependency on PHP ^5.6|^7.0|^7.1|^7.2