ci: tacd: use only cargo clippy and not cargo check as well

[hnez]

The checks performed by running cargo check are a subset of what cargo clippy checks for (as indicated by cargo clippy [using cargo check in the background]):

https://github.com/rust-lang/rust-clippy/blob/c154754b74577906c5d55d57f7daeff02d6a33e7/src/main.rs#L59-L105

Running both is thus a waste of CPU cycles. Run cargo clippy only.

[KarlK90]

LGTM, we could probably run the tests after all lints have been satisfied to catch malformed code and save some more cycles.

[hnez]

Running lints and tests in sequence would:

• Increase our push-to-CI-done latency. Which is kind of annoying when e.g. updating a branch to the recent main.
• Mean we would only see actual build problems after all lints are fixed.

I think these drawbacks make it not worth it.

---

I do however have another idea with regards to CI jobs:

We could also run the basic cargo clippy job with the current rust version we use in meta-lxatac to make sure we do not break compatibility with said version (which already happened and will happen again, for example when #42 is merged).