Bug: --config is relative to --manifest-path

[kpreid]

Describe the bug

If both --manifest-path and --config are specified, the pathname given for the latter is taken as relative to the former instead of the current directory.

To reproduce

$ cargo deny --manifest-path=foo/Cargo.toml check --config=bar/deny.toml
2025-02-26 17:37:15 [WARN] config path 'foo/bar/deny.toml' doesn't exist, falling back to default config

cargo-deny version

0.18.0

What OS were you running cargo-deny on?

MacOS

Additional context

No response