feat(options): use version string from file for --version flag
Replaces `clap::crate_version!()` with `include_str!(concat!(env!
("OUT_DIR"), "/version_string.txt"))` for the `--version` flag. This
ensures that the version string, which includes build metadata like Git
hash and build date, is properly displayed when `eza --version` is run,
maintaining feature parity with previous behavior.