[SPI-2066]: replace deprecated GEANT4_BUILD_CXXSTD with CMAKE_CXX_STANDARD

There was a warning in cmake that GEANT4_BUILD_CXXSTD is deprecated, it is replaced with the cmake standard variable for the c++ standard

projects/CMakeLists.txt

@@ -452,7 +452,11 @@ LCGPackage_add(
                -DGEANT4_USE_USOLIDS=ALL
                -DVecGeom_DIR=${VecGeom_home}/lib/cmake/VecGeom
              ENDIF
-             -DGEANT4_BUILD_CXXSTD=${CMAKE_CXX_STANDARD}
+             IF <VERSION> VERSION_LESS 11.00 THEN
+                 -DGEANT4_BUILD_CXXSTD=${CMAKE_CXX_STANDARD}
+             ELSE
+                 -DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}
+             ENDIF
              -DGEANT4_USE_PYTHON=ON
   BUILD_COMMAND ${MAKE}
   INSTALL_COMMAND make install