Set minimal Qt version according to used Qt API to 5.11
hello @cordlandwehr, I'd like to ask a question: why set the required version from 5.4 straight to 5.11? I'm asking this because, currently, the version of the
Qt5-defaultpackage in Ubuntu 18.04 LTS, for example, is the 5.9.5 version. So I thought maybe 5.9 version should be the minimum requirement, thus making it easily accessible to a broader community. Thanks!