crate_universe is incompatible with Bazel 8.0.0

[jthemphill]

Attempting to build example 05-deps-cargo on an M1 Mac. The example builds great on Bazel 7 but fails on Bazel 8.

I made two changes.

First, I bumped .bazelversion in the examples repository:

- 7.2.1
+ 8.0.0

The build then failed. I thought maybe the newest version of rules_rust could address the issue. So I bumped the version of rules_rust in MODULE.bazel:

- bazel_dep(name = "rules_rust", version = "0.47.1")
+ bazel_dep(name = "rules_rust", version = "0.56.0")

Running the build with Bazel 8 and rules_rust 0.56.0:

05-deps-cargo % bazel build //...
WARNING: Couldn't auto load rules or symbols, because no dependency on module/repository 'rules_android' found. This will result in a failure if there's a reference to those rules or symbols.
ERROR: /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/external/rules_rust+/crate_universe/extensions.bzl:363:17: Traceback (most recent call last):
        File "/private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/external/rules_rust+/crate_universe/extensions.bzl", line 459, column 37, in _crate_impl
                _generate_hub_and_spokes(
        File "/private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/external/rules_rust+/crate_universe/extensions.bzl", line 144, column 16, in _generate_hub_and_spokes
                cargo_bazel([
        File "/private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/external/rules_rust+/crate_universe/extensions.bzl", line 363, column 17, in run
                fail("%s returned with exit code %d:\n%s" % (pretty_args, result.return_code, result.stderr))
Error in fail: /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/modextwd/rules_rust++crate/cargo-bazel generate --cargo-lockfile /Users/jhemphill/oss/bazelbuild/examples/rust-examples/05-deps-cargo/Cargo.lock --config /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/modextwd/rules_rust++crate/crates/config.json --splicing-manifest /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/modextwd/rules_rust++crate/crates/splicing_manifest.json --repository-dir /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/modextwd/rules_rust++crate/crates --metadata /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/modextwd/rules_rust++crate/crates/splicing-output/metadata.json --repin --lockfile /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/modextwd/rules_rust++crate/crates/lockfile.json --nonhermetic-root-bazel-workspace-dir /Users/jhemphill/oss/bazelbuild/examples/rust-examples/05-deps-cargo --paths-to-track /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/modextwd/rules_rust++crate/paths-to-track --warnings-output-path /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/modextwd/rules_rust++crate/warnings-output-file --cargo /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/external/rules_rust++rust_host_tools+rust_host_tools/bin/cargo --rustc /private/var/tmp/_bazel_jhemphill/a3385e184eb75f0cb537a24f915a0ff0/external/rules_rust++rust_host_tools+rust_host_tools/bin/rustc returned with exit code 1:
Error: Package "all_crate_deps" target "all_crate_deps" had an absolute source path "/dev/null", which is not supported