ci: add separate cargo test

[wischli]

No ticket

In #231 none of the CI tests failed but cargo test was broken for the did pallet. This should be fixed by #235. However, in #235 we stumbled into the same error. Thus, I think we should add a separate `cargo test step to the CI as proposed here.

Checklist:

• I have verified that the code works
  • No panics! (checked arithmetic ops, no indexing array[3] use get(3), ...)
• I have verified that the code is easy to understand
• This PR does not introduce new custom types
• I have left the code in a better state
• I have documented the changes (where applicable)

[wischli]

CI failure proves my point of adding this to the CI. They should be fixed after merging #235 as mentioned above.

[ntn-x2]

Should we add --all-targets also to cargo test? I guess we could go for cargo test --all --all-targets and cargo test --all --all-features --all-targets?

[wischli]

Should we add --all-targets also to cargo test? I guess we could go for cargo test --all --all-targets and cargo test --all --all-features --all-targets?

Yeah, that sounds good.

[weichweich]

my only objection is that this will increase the load on the server. We have 2 concurrent jobs at the moment. Maybe we should increase that to 3 or 4. 🤔