ci: update codecov config

[vie-serendipity]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespace from that line: /kind bug /kind documentation /kind enhancement /kind good-first-issue /kind feature /kind question /kind design /sig ai /sig iot /sig network /sig storage

/kind enhancement

What this PR does / why we need it:

A lot auto-generated files exist in this project. They lack associated tests and should be omitted from Codecov's coverage analysis.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

None

other Note

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 53.14%. Comparing base (525a0f7) to head (2d2ee6e).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2000 +/- ## ========================================== + Coverage 53.05% 53.14% +0.08% ========================================== Files 176 175 -1 Lines 20944 20910 -34 ========================================== Hits 11112 11112 + Misses 8884 8850 -34 Partials 948 948 ``` | [Flag](https://app.codecov.io/gh/openyurtio/openyurt/pull/2000/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openyurtio) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/openyurtio/openyurt/pull/2000/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openyurtio) | `53.14% <ø> (+0.08%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openyurtio#carryforward-flags-in-the-pull-request-comment) to find out more.

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[rambohe-ch]

/lgtm