[skip-changelog] Add Codecov token

[umbynos]

Please check if the PR fulfills these requirements

• The PR has no duplicates (please search among the Pull Requests
  before creating one)
• Tests for the changes have been added (for bug fixes / features)

• What kind of change does this PR introduce?

CI enhancement

• What is the current behavior?

The CI sometime fails with:

[2023-09-04T14:00:44.591Z] ['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')}

• What is the new behavior?

According to this, it should remove the problem

• Does this PR introduce a breaking change?

no

• Other information: