Update PHP requirement in README #16774
Guess doesn't make sense to show PHP 5.5 as requirement, even though Matomo 3 will be in LTS for a while...
We also should maybe update this page so the commands at least install php 7.2: https://matomo.org/docs/requirements/#recommended-configuration
I guess we can generalize them. At least on Debian e.g. php-fpm is always a metapackage that installs the proper version from the repo.