Support expanded version flag in shims

[kate-goldenring]

Adds support for fully spelled out version flag in shims. Currently only -v is supported. I'm a maintainer of the Spin shim and some users have found this experience confusing for debugging. For example, in the Spin shim:

$ /usr/local/bin/containerd-shim-spin-v2 -version
thread 'main' panicked at /home/runner/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/containerd-shimkit-0.1.1/src/sandbox/cli.rs:226:38:
called `Result::unwrap()` on an `Err` value: InvalidArgument("flag provided but not defined: -version")
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Aborted (core dumped)

$ /usr/local/bin/containerd-shim-spin-v2 -v
containerd-shim-spin-v2:
  Runtime: spin
  Version: 0.22.0
  Revision: b22980861884b65