Change from QT5 to QT6

TODO:
- Make the version more generic throughout the CMake scripts

Changes to be committed:
	modified:   CMakeLists.txt

CMakeLists.txt

@@ -174,7 +174,7 @@ list ( FILTER SOURCES EXCLUDE REGEX ".*Runnables.*" )
 
 # Add library target EGOA to be build from the source files
 add_library ( EGOA ${SOURCES} )
-target_link_libraries ( EGOA ${QT5_LIBRARIES} )
+target_link_libraries ( EGOA ${QT6_LIBRARIES} )
 
 # Add subdirectory here the source directory with the corresponding
 # CMakeLists.txt