While the goal is laudable, by we arbitrarily restrict the window of supported versions of PHP by allowing the lowest supported versions of a library's dependency (which may have an even lower ceiling than us) to dictate our maximum supported version via the test suite.
Since we're now testing against multiple versions of PHP, that will provide a better show of our range of supported PHP versions, and it's down to consuming libraries to make sure they are compatible with any sub-dependency requirements
While the goal is laudable, by we arbitrarily restrict the window of supported versions of PHP by allowing the lowest supported versions of a library's dependency (which may have an even lower ceiling than us) to dictate our maximum supported version via the test suite.
Since we're now testing against multiple versions of PHP, that will provide a better show of our range of supported PHP versions, and it's down to consuming libraries to make sure they are compatible with any sub-dependency requirements