Document --shout, --version and --times in the README usage section #70

In README.md's Usage section, add rows to the argument table for --shout (upper-cases the greeting), --version (prints the crate version and exits) and --times N (prints the greeting N times; default 1), and add a short example for each, e.g. cargo run -- --shout Ada giving HELLO, ADA!. Verify examples against the real binary. Leave the other sections unchanged.

Definition of done

• cargo run -- --shout Ada passes.
• cargo run -- --times 2 Ada passes.
• cargo run -- --version passes.