tests: upgraded tarpaulin and added derive macro coverage

[tyrone-wu]

Upgraded tarpaulin to new the new maintainer, added coverage for derive macro, and added an example.

Motivation

Resolves #1144

Solution

Here's the codecov for this PR. https://app.codecov.io/gh/tyrone-wu/kube/tree/tests%2Fupdate-code-coverage

• Bump to latest (currently 0.27.3) from our pin at 0.18.5 from Nov 2021
  • Upgraded tarpaulin to the new maintainer.
• Find a better GH Action approach (see below for the issues with actions-rs/tarpaulin) - taike-e install
  • For now, this uses the tarpaulin dev version from https://github.com/xd009642/tarpaulin since the false negative coverage isn't in release yet (not sure when it'll be in). Once it's in release, it can be switched back to taike-e install.
• Try the proc macro coverage so that we can get credit for tests in kube-derive (currently it looks bad but it is tested)
  • https://app.codecov.io/gh/tyrone-wu/kube/tree/tests%2Fupdate-code-coverage/kube-derive
  • The syn dependency used v1 in both runtime-macros and runtime-macros-derive, and it caused some error when running them against this projects derive macros. I'm not entirely sure if they're being maintained anymore since last update a while ago, and syn v1 was a pretty ancient version. I ended up forking and upgrading it to v2 on my own https://github.com/tyrone-wu/runtime-macros. (tbh, I'm not entirely sure what runtime-macros does internally, but I tried upgraded syn so that it's compatible with kube's derive macros, and it seems to be getting the coverage which is good I think? 😅)
• Do an all-features build in coverage (to ensure numbers are the most accurate and the most tests run)
• Try to include one or two examples if it can be done quickly (better to improve coverage with actual integration tests)
  • Tarpaulin now includes the crd_derive_schema example, and default feature is now the default of running it (I think).

I noticed the codecov step uses v3. Would you prefer also upgrading it to latest v4? I'm not sure what things this adds or changes so it might not be necessary.

[clux]

Thank you so much for this. This looks great on paper. Minor nit on git pins, and CI doesn't like it atm but I guess that is token perms.

[2024-04-11T21:53:06.477Z] ['error'] There was an error running the uploader: Error uploading to [https://codecov.io:](https://codecov.io/) Error: There was an error fetching the storage URL during POST: 404 - {'detail': ErrorDetail(string='Unable to locate build via Github Actions API. Please upload with the Codecov repository upload token to resolve issue.', code='not_found')}

Will run a quick local verify tomorrow. EDIT: ran it, works great.

codecov step uses v3

yeah, dw about that. I'll get in dependabot to update actions for us afterwards.

[clux]

Thank you so much!