fix the PHPUnit caution block

[loru88]

No description provided.

[stof]

@loru88 it looks like your one v3.x branch contains extra commits compared to the branch in the main repo, which get included in your PR.
Please clean the history of your PR to submit only the relevant work (hint: it is generally better to create a dedicated branch for each PR, from the current state of the upstream branch, instead of using your own v3.x branch and hoping it never diverges from the upstream branch in the future)