Version 2.1.2 of the addin was checking for qmake.exe but Version 2.2.0 is checking for Qt5Core.dll.
If you're using the infix for configure (i.e. 'TRS') all the dlls have this infix: Qt5CoreTRS.dll and the addin will grumble around that it can't find "Qt5Core.dll". Surprise, surprise!
So you're no longer able to use the addin with own Qt builds.