Centralize crate versions and update `regex-syntax` to v0.8

[rneswold]

This pull-request has two commit:

• one puts all the dependency versions in the workspace Cargo.toml file. Now you can update the version of a dependent crate in one spot and all sub-crates will use it.
• bump the regex-syntax crate to v0.8

Each of these commits was tested with cargo test and passed.

[ltratt]

Thanks!