cross: Unit tests failing during NixOS build

Checklist

I’ve looked through the issues and pull requests for similar reports

Describe your issue

When updating the NixOS package from 0.2.1 to 0.2.4, one of tests fail during execution. Log is below:

test docker::shared::tests::directories::test_docker_in_docker ... ok
test docker::shared::tests::directories::test_host ... FAILED
test tests::toml::toml_check ... ok
test cross_toml::tests::merge ... ok

failures:

---- docker::shared::tests::directories::test_host stdout ----
Error: Permission denied (os error 13)

Location:
    src/docker/shared.rs:965:13
thread 'docker::shared::tests::directories::test_host' panicked at 'assertion failed: `(left == right)`
  left: `1`,
 right: `0`: the test returned a termination value with a non-zero status code (1) which indicates a failure', /build/rustc-1.61.0-src/library/test/src/lib.rs:186:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace


failures:
    docker::shared::tests::directories::test_host

The affected code is: https://github.com/cross-rs/cross/blob/6cd09b3eb28da7f4e21ee9e3ecee89a3d309c1dc/src/docker/shared.rs#L966-L983