Request: Instructions to reproduce fiat-crypto files

[jhand2]

Would it be feasible to document the configurations were used to generate the fiat-crypto arithmetic used in this crate? In particular:

In particular:

• Which version of fiat-crypto was used as the source
• Which version of fiat-constify was used

This would help to be able to ensure the files in this crate match some specific fiat-crypto release.