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/ci.yml

@@ -161,7 +161,7 @@ jobs:
     - name: 🧪 Test Python code
       run: pytest --cov=./ --cov-report=xml ir_axioms/ tests/unit/ --ignore=ir_axioms/backend/ --ignore=ir_axioms/cli.py
     - name: 📤 Upload coverage to Codecov
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v4
       if: matrix.python == '3.9' && matrix.os == 'ubuntu-latest'
       with:
         token: ${{ secrets.CODECOV_TOKEN }}
@@ -199,7 +199,7 @@ jobs:
     - name: 🧪 Test Python code
       run: pytest --cov=./ --cov-report=xml tests/integration/${{ matrix.backend }}/ ${{ matrix.backend == 'pyterrier' && 'ir_axioms/cli.py' || '' }}
     - name: 📤 Upload coverage to Codecov
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v4
       if: matrix.python == '3.9' && matrix.os == 'ubuntu-latest'
       with:
         token: ${{ secrets.CODECOV_TOKEN }}