rustc_compile_action: deps required to be a list instead of a depset in 0.67.0

While migrating my project from 0.63 to 0.67 I found something strange a bit, so, wanted to double check. Here's my PR: https://github.com/mvukov/rules_ros2/pull/541/files. In short, I do code-generation in an aspect where I also compile rust code. That means that deps for the compile actions are pooled via the dep graph. A natural way to handle deps is via a depset which was the case until recently. So, instead of doing something like:
```
deps = depset(direct=direct_deps, transitive=transitive_deps)
```
I have to do now:
```
deps = direct_deps + transitive_deps.to_list()
```
Issues I see:
* calling to_list(), which can be a performance hit,
* it doesn't make a lot of sense as deps are converted to a depset internally https://github.com/bazelbuild/rules_rust/blob/0.67.0/rust/private/rustc.bzl#L1211.

I guess there was some reasoning behind this change, would be great if someone can share the rationale.