Bump codecov/codecov-action from 5 to 6

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 5 to 6.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v5...v6)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -85,7 +85,7 @@ jobs:
           URSIM_VERSION: ${{matrix.env.URSIM_VERSION}}
       - name: Upload test results to Codecov
         if: ${{ !cancelled() && steps.build.outcome == 'success' }}
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           fail_ci_if_error: true
           files: build/junit.xml
@@ -102,7 +102,7 @@ jobs:
         run: cd build && gcovr -r .. --xml coverage.xml --gcov-ignore-parse-errors negative_hits.warn_once_per_file --exclude "../3rdparty"
       - name: Upload coverage reports to Codecov with GitHub Action
         if: ${{ !cancelled() && steps.build.outcome == 'success' }}
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           fail_ci_if_error: true
           files: build/coverage.xml
@@ -168,7 +168,7 @@ jobs:
           BATS_LIB_PATH: ${{ steps.setup-bats.outputs.lib-path }}
         run: bundle exec bashcov --skip-uncovered bats tests/test_start_ursim.bats
       - name: Upload coverage reports to Codecov with GitHub Action
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           fail_ci_if_error: true
           flags: start_ursim