[binstall] Expose version

[storopoli]

Some devcontainers need to have rust set to a specific version for MSRV.
That can make the binstall feature fail because it always fetch the latest version and sometimes it is incompatible with the cargo version that is installed in the devcontainer.

[lee-orr]

I'm uncertain what the solution to this is? Do you mean exposing a way to binstall a specific package version, or a specific version of binstall?

[storopoli]

specific version of binstall