fix _MSC_VER version to check for std::filesystem

[gcerretani]

According to

json/include/nlohmann/detail/macro_scope.hpp

Line 72 in cc59ab1

// no filesystem support before MSVC 19.14: https://en.cppreference.com/w/cpp/compiler_support

MSVC supports std::filesystem since 19.14, (Visual Studio 2017 version 15.7) that has _MSC_VER == 1914 according to Microsoft documentation, but the check is done against a not existing value 1940 (latest Visual Studio 2022 has _MSC_VER == 1930).

I just change this value.

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[nlohmann]

Thanks for the PR! Looks like a copy/paste error on my side. I will happily merge this if the CI accepts it. I am not using MSVC myself...

[coveralls]

Coverage remained the same at 100.0% when pulling dd2a42e on gcerretani:fix_filesystem_msvc into cc59ab1 on nlohmann:develop.

[nlohmann]

Looks good to me.

[nlohmann]

Thanks!