Add recent/minimal lock files and tooling

As we do in `rust-bitcoin` add two lock files, one with minimal
dependency version numbers and one with recent dependency version
numbers

The minimal was created using `-Z minimal-versions` then tested by
building with `RUSTUP_TOOLCHAIN=1.56.1 cargo --locked check`.

The recent was created by the `contrib/test.sh` script with MSRV
toolchain.

Add script to update the lock files and a `just` command to run it.

Author: tcharding