Deprecation of interface libraries only works from CMake 3.19

cmake/modules/DuneProject.cmake

@@ -246,7 +246,7 @@ endif()")
       set(DUNE_DEPRECATED_LIBRARY_ALIASES "${DUNE_DEPRECATED_LIBRARY_ALIASES}
 add_library(${_alias_name} INTERFACE)
 target_link_libraries(${_alias_name} INTERFACE ${_export_name})
-if(CMAKE_VERSION VERSION_GREATER_EQUAL \"3.17\")
+if(CMAKE_VERSION VERSION_GREATER_EQUAL \"3.19\")
   set_property(TARGET ${_alias_name} PROPERTY DEPRECATION \"Use ${_export_name} instead.\")
 endif()")
       unset(_alias_name)

cmake/pkg/dune-common-config.cmake.in

@@ -29,6 +29,6 @@ endif(NOT @DUNE_MOD_NAME@_FOUND)
 
 add_library(dunecommon INTERFACE)
 target_link_libraries(dunecommon INTERFACE Dune::Common)
-if(CMAKE_VERSION VERSION_GREATER_EQUAL \"3.17\")
-  set_property(TARGET dunecommon PROPERTY DEPRECATION \"Use Dune::Common instead.\")
+if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.19")
+  set_property(TARGET dunecommon PROPERTY DEPRECATION "Use Dune::Common instead.")
 endif()