Currently CI is broken because we use the latest version of `rustfmt`
and `clippy` in CI. We can resolve the `rustfmt` issue permanently by
removing the `required_version` config option. We also need to fix the
latest clippy warnings.
Done as a single patch so that all patches pass CI.
As we did in `rust-bitcoin` introduced a `rustfmt` configuration file
that is palatable to devs.
Do not run formatter, that is done as a separate patch to assist review.
We do not currently use `rustfmt`, this is a nuisance for devs who
routinely work on code bases that do use rustfmt who often have their
editors set to format on save. We can make the life of such devs much
better by explicitly disabling formatting using `rustfmt.toml`.
ref: https://rust-lang.github.io/rustfmt/?version=v1.4.38&search=#disable_all_formatting
Tobin C. Harding