Doesn't work with PHP 7.2 due to JsonLD issue #758
Description
At the moment unit tests fail on PHP 7.2. The JsonLD library that we depend on doesn't work with PHP 7.2 due to the use of object keyword and also some issues with the count() function:
There is a fix available in a PR:
I think we will wait for the problem to be fixed upstream in JsonLD. Once this works again, we should change our Travis configuration so that PHP 7.2 is no longer in the allowed to fail category.