feat: Lower the required rust version to 1.66.1

Both Red Hat Enterprise Linux 8 and 9, Ubuntu 22.04 (LTS) ships with rustc 1.66.1. Debian 12 ships with rustc 1.63.0.

It would be nice to have this tool available on those distros as well, which are long term stable environments and preferred in production environments.

I've not a little bit quick research, and I see that this will require some tweaks to other dependencies. Unfortunately, my rust-cargo-foo is way too low to properly dig into this deeper right now.

The issue does not name a file or test. Start by inspecting the project's Rust version and dependency constraints, then check whether the tool builds with rustc 1.66.1 and the listed dependency adjustments. Done means the minimum supported Rust version is 1.66.1 and the project builds successfully on that compiler.

Written by the indexing model from the issue text.