Bump codecov/codecov-action from 3 to 4

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 3 to 4.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v3...v4)

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

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

.github/workflows/Documentation.yml

@@ -25,6 +25,6 @@ jobs:
  - uses: julia-actions/julia-processcoverage@v1
  with:
  directories: src
- - uses: codecov/codecov-action@v3
+ - uses: codecov/codecov-action@v4
  with:
  files: lcov.info

.github/workflows/Downstream.yml

@@ -49,6 +49,6 @@ jobs:
  exit(0) # Exit immediately, as a success
  end
  - uses: julia-actions/julia-processcoverage@v1
- - uses: codecov/codecov-action@v3
+ - uses: codecov/codecov-action@v4
  with:
  file: lcov.info