tests: check pedantic C++14

Author: henryiii

tests/CMakeLists.txt

@@ -412,7 +412,7 @@ function(pybind11_enable_warnings target_name)
               -Wundef
               -Wnon-virtual-dtor)
     target_link_options(${target_name} PRIVATE -Werror -Wodr -Wlto-type-mismatch)
-    if(DEFINED CMAKE_CXX_STANDARD AND NOT CMAKE_CXX_STANDARD VERSION_LESS 20)
+    if(DEFINED CMAKE_CXX_STANDARD AND NOT CMAKE_CXX_STANDARD VERSION_LESS 14)
       target_compile_options(${target_name} PRIVATE -Wpedantic)
     endif()
   endif()