[Meta] Consider what to do with out of sync localized READMEs

#3368 / #3390 moved 0.6.x to .NET 8.0, but remnants of .NET 6.0 can still be seen in some localized documentation:

https://github.com/OpenTabletDriver/OpenTabletDriver/blob/902d0d5873eed2e2a4cd882c43d5a723ea7a78e8/docs/README_KO.md?plain=1#L37-L39

(among others)

This is likely going to be a ongoing problem whenever README contents change.

While adjusting localized content is occasionally possible (especially when just numbers and URLs change, as seen in #3387), not everything can be updated by people not fluent in the language.

This means we either need to autogenerate localized READMEs (would have to check what other projects do), have a person responsible for localization in their respective language, or just put a "last modified" date at the top of the file? Other solutions are welcome too.

Alternatively we can get rid of the localized READMEs, but I prefer the positive social implications that having these do (both for contributors and users), so I would see that only as a last resort option.

Start by reviewing docs/README_KO.md and the related changes in #3368, #3390, and #3387, then inspect the other localized README files for similar drift. Compare the available maintenance approaches described in the issue and document a clear decision, scope, and completion criteria for keeping localized READMEs synchronized.