Fix a qt deprecation warning in cmake
As explained here:
Deprecated since version 3.14: This command was originally added to support Qt 3 before the add_custom_command() command was sufficiently mature. The FindQt4 module provides the qt4_wrap_ui() macro, which should be used instead for Qt 4 projects. For projects using Qt 5 or later, use the equivalent macro provided by Qt itself (e.g. Qt 5 provides qt5_wrap_ui()).
Edited by jvoisin