[Trivial] Conform to snake_case for temporary crate name

[JackMordaunt]

When running cargo script I get this warning:

[cargo-make] INFO - Execute Command: "cargo" "script" "/var/folders/dm/hk5h5c8n0rg2cvsn67d0kjd00000gn/T/cargo-make/Yso0d56VD0.rs"
    Updating crates.io index
   Compiling Yso0d56VD0 v0.1.0 (/Users/jack/.cargo/script-cache/file-Yso0d56VD0-195512b2c76e7c26)
warning: crate `Yso0d56VD0` should have a snake case name such as `yso0d56_vd0`
  |
  = note: #[warn(non_snake_case)] on by default

I think it would be nice to silence this warning by ensuring the generated crate name is snake_case. Perhaps even just lowercase will suffice.