Cargo.toml edition = "2021"

[lizelive]

------
 > Collecting configuration metadata:
#7 0.245 error: failed to parse manifest at `/dockerfile/contract-rs/Cargo.toml`
#7 0.245 
#7 0.245 Caused by:
#7 0.245   failed to parse the `edition` key
#7 0.245 
#7 0.245 Caused by:
#7 0.245   supported edition values are `2015` or `2018`, but `2021` is unknown
------

[austenadler]

I believe this is due to the cargo = "0.40" version here: https://github.com/denzp/cargo-wharf/blob/ef460f80bf8fe1b9ec95dad321a79929d67f0c45/cargo-container-tools/Cargo.toml#12. The latest version of cargo has Version2021 here

I just requested this PR: #47 that I haven't tested myself because I haven't been able to build the images for various reasons. If the PR works please comment and maybe dev will merge.