Update cxxbridge-cmd example.

[sayrer]

This is just a start. I am not sure how the lockfiles in examples/using_cxx were generated. This does work for me, but I don't have all the lockfiles that the examples do.

[sayrer]

I also had to call the rust_cxx_bridge macro this way, so that "cxx.h" would be available.

rust_cxx_bridge(
    name = "bridge",
    src = "src/lib.rs",
    deps = [
        "//3rdparty/crates:cxx_cc",
    ],
)