Some letters get changed when desc writes to the description file.

[Farbfetzen]

Steps to reproduce:

1. Have a package description file with an Authors@R field like this: Authors@R: person("Foo", "ńęĘłŁźż", role = "aut"). Not a real name, just some letters from the polish alphabet.
2. Run d <- description$new()
3. Note that the name in d is still correct.
4. Run d$write()
5. Observe the wrong name in the description file: Authors@R: person("Foo", "neElLzz", role = "aut")

This is problematic when using usethis::use_package() or usethis::use_version(), for example.

OS: Windows 10
R: 4.0.5
RStudio: 1.4.1103
desc version: 1.3.0