book need to update accroding to the template build command change

[dassio]

the recent template commit: aya-rs/aya-template@5811d6f make the getting started guide command cargo xtask build-ebpf not working.
need to update the book and example code to reflect this change.

the build and running command should be:

cargo build 

RUST_LOG=info cargo run -- --iface enp5s0

[tamird]

Can you send a pull request?

[tamird]

Note that the book doesn't mention the template so it is technically not broken. But we should update the book examples to the latest template.