Install error: failed to parse the `edition` key

[jfriend00]

If you get an install error that has these in it:

failed to parse theeditionkey

or

supported edition values are2015or2018, but2021is unknown

Then, it's likely because your version of rust is out of date and you need to update it. I was able to update mine by just typing:

rustup update

And, then the installation issue disappeared. It might be useful if the doc for this module explains this dependency.

[alexgorbatchev]

I think you wanted to post this elsewhere, this issues doesn't make sense in the context of this repo.