Fix CMake interface include directories

[myd7349]

Fix #319 .
It turns out to be a mistake I made in #312 .
In that PR, I changed these lines:

   INSTALL( TARGETS g3logger
            EXPORT g3logger-targets
               ARCHIVE DESTINATION ${CPACK_PACKAGING_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}
               LIBRARY DESTINATION ${CPACK_PACKAGING_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}
               COMPONENT libraries)

to:

INSTALL( TARGETS g3logger
   INSTALL( TARGETS g3logger
            EXPORT g3logger-targets
            ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
            LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
            RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
            INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
            COMPONENT libraries)

but I forgot to take care of COMPONENT .
COMPONENT libraries should be together with LIBRARY/ARCHIVE/RUNTIME, but not with INCLUDES.
And this mistake causes INTERFACE_INCLUDE_DIRECTORIES to be set incorrectly in g3loggerTargets.cmake:

set_target_properties(g3logger PROPERTIES
  INTERFACE_COMPILE_FEATURES "cxx_variable_templates"
  INTERFACE_INCLUDE_DIRECTORIES "${_IMPORT_PREFIX}/include;${_IMPORT_PREFIX}/COMPONENT;${_IMPORT_PREFIX}/libraries"
  INTERFACE_LINK_LIBRARIES "Threads::Threads;dbghelp"
)

which, instead, should be set as:

set_target_properties(g3logger PROPERTIES
  INTERFACE_COMPILE_FEATURES "cxx_variable_templates"
  INTERFACE_INCLUDE_DIRECTORIES "${_IMPORT_PREFIX}/include"
  INTERFACE_LINK_LIBRARIES "Threads::Threads;dbghelp"
)

[myd7349]

The COMPONENT is useful when you want to create a package that give the users some options to choose which components should be installed and which should not. For example, when I create a NSIS package of g3log on Windows and run the installer, I will get this: