Document `--luksversion` usage in `README.md`. Also, provide some background on what version to use in relation to Ubuntu version. _https://github.com/square/luks2crypt/issues/66#issuecomment-844789565_
Document
--luksversionusage inREADME.md. Also, provide some background on what version to use in relation to Ubuntu version.#66 (comment)