Can't inherit a CARGO_PKG_README which was missing from the workspace

Hello!

I'm running into this error when upgrading to rules rust 0.61 (from 0.57):
```
Can't inherit a CARGO_PKG_README which was missing from the workspace
```
Digged a bit, and this patch makes the build work:
```
diff --git cargo/cargo_toml_variable_extractor/main.rs cargo/cargo_toml_variable_extractor/main.rs
index 8e67307e..4562c66d 100644
--- cargo/cargo_toml_variable_extractor/main.rs
+++ cargo/cargo_toml_variable_extractor/main.rs
@@ -233,9 +233,7 @@ fn print_inheritable_path(
.join(std::path::MAIN_SEPARATOR_STR);
Some(joined)
}
- (Some(InheritableString::Inherit(_)), None) => {
- panic!("Can't inherit a {key} which was missing from the workspace")
- }
+ (Some(InheritableString::Inherit(_)), None) => None,
_ => None,
};
print_optional_env_str(out, key, maybe_path.as_deref());
```

However not sure it's what is wanted (did not really dig into the whole inheritance thing). I can open a PR as is if that what we want, but I guess it'll break some other config?