Check whether a package name is a valid npm package name.
use valid_npm_name::ValidName;
let foo = ValidName::parse("foo").unwrap();
assert_eq!("foo", foo.to_string());
let bar_name = ValidName::parse("bar").unwrap();
let bar = bar_name.as_ref();
assert_eq!("bar", bar);
let baz = ValidName::parse("baz").unwrap();
assert_eq!("baz", baz.as_str());