AzureCliCredential cannot find az on windows (10?)

[gzp79]

rust Command cannot find az command on (some) windows systems. Most certainly it is related to how command is implemented:
see rust-lang/rust#42791 and https://doc.rust-lang.org/nightly/std/process/struct.Command.html.

I think az is az.cmd on windows and it should be called with cmd /c

let az_command = Command::new("cmd")
            .args(&[
                "/C",
                "az",
                "account",
                "get-access-token",
                "--output",
                "json",
                "--resource",
                resource,
            ])
            .output();