ci: Minor adjustments for dependabot pull requests

[marcospereira]

What?

Two minor changes based on the first PR (#344) opened by dependabot.

• Since it creates a branch in the repository instead of a fork, it runs the workflows twice (one for the PR and one for the push). Therefore, pushes will only run now when it is for the main branch.
• It should not try to upload code coverage.

[codecov[bot]]

Codecov Report

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

Project coverage is 91.31%. Comparing base (376f241) to head (e0d6ac5). Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #345 +/- ## ========================================= Coverage 91.31% 91.31% Complexity 1218 1218 ========================================= Files 76 76 Lines 3168 3168 Branches 493 493 ========================================= Hits 2893 2893 Misses 164 164 Partials 111 111 ```

:umbrella: View full report in Codecov by Sentry.
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[marcospereira]

Updating codecov/codecov-action to version v4 broke Codecov uploading because now a token is required:

https://github.com/codecov/codecov-action/blob/v4/README.md#breaking-changes

Example of broken workflow run:

https://github.com/casid/jte/actions/runs/8571119047

Tokenless uploading is unsupported. However, PRs made from forks to the upstream public repos will support tokenless (e.g. contributors to OS projects do not need the upstream repo's Codecov token)

The Codecov docs related token setup are here: https://docs.codecov.com/docs/adding-the-codecov-token.

@casid, it seems I can remove e545b7f, but you will need to create the Codecov token.

[casid]

Hi @marcospereira!

Thanks for the hint with the token, I've added it as a secret.

I'm merging this PR now.