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)
Adds a CodeCov token

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

Signed-off-by: dependabot[bot] <[email protected]>

Add CodeCov token

add codecov token with secret

.github/workflows/main.yml

@@ -35,10 +35,11 @@ jobs:
 
     - run: bundle exec rspec
 
-    - uses: codecov/codecov-action@v3
+    - uses: codecov/codecov-action@v4
       with:
         files: ./coverage/coverage.xml
         fail_ci_if_error: true # optional (default = false)
+        token: ${{ secrets.CODECOV_TOKEN }}
         verbose: true # optional (default = false)
       if: matrix.ruby == 3.2