Add missing coverage configuration section to pyproject.toml

[djhoese]

CI was failing to upload coveralls for two reasons:

1. When we moved to pyproject.toml one of the config sections regarding coverage was forgotten.

2. A new security feature in git was causing the coveralls action to fail. I've fixed this upstream.

   • [ ] Closes #xxxx
   • [ ] Tests added
   • [ ] Fully documented

[codecov[bot]]

Codecov Report

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

Project coverage is 95.95%. Comparing base (c9aabb7) to head (1742616). Report is 3 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #2797 +/- ## ======================================= Coverage 95.95% 95.95% ======================================= Files 379 379 Lines 53861 53861 ======================================= Hits 51680 51680 Misses 2181 2181 ``` | [Flag](https://app.codecov.io/gh/pytroll/satpy/pull/2797/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pytroll) | Coverage Δ | | |---|---|---| | [behaviourtests](https://app.codecov.io/gh/pytroll/satpy/pull/2797/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pytroll) | `4.09% <ø> (ø)` | | | [unittests](https://app.codecov.io/gh/pytroll/satpy/pull/2797/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pytroll) | `96.04% <ø> (ø)` | | 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=pytroll#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.

[mraspaud]

Thanks for fixing this!