Bump codecov/codecov-action from 3 to 4 (#831)

* 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] <[email protected]>

* expose the token, this is intentional.
https://community.codecov.com/t/upload-issues-unable-to-locate-build-via-github-actions-api/3954

---------

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Umberto Baldi <[email protected]>

.github/workflows/test-go-task.yml

@@ -96,11 +96,26 @@ jobs:
           GO_MODULE_PATH: ${{ matrix.module.path }}
         run: task go:test
 
+      # A token is used to avoid intermittent spurious job failures caused by rate limiting.
+      - name: Set up Codecov upload token
+        if: runner.os == 'Linux'
+        run: |
+          if [[ "${{ github.repository }}" == "arduino/arduino-create-agent" ]]; then
+            # In order to avoid uploads of data from forks, only use the token for runs in the arduino/arduino-create-agent repo.
+            # Token is intentionally exposed.
+            # See: https://community.codecov.com/t/upload-issues-unable-to-locate-build-via-github-actions-api/3954
+            CODECOV_TOKEN=fe64847a-368e-4f95-9212-1f7a6835043f
+          else
+            # codecov/codecov-action does unauthenticated upload if empty string is passed via the `token` input.
+            CODECOV_TOKEN=""
+          fi
+          echo "CODECOV_TOKEN=$CODECOV_TOKEN" >> "$GITHUB_ENV"
+
       - name: Send unit tests coverage to Codecov
         if: runner.os == 'Linux'
-        uses: codecov/codecov-action@v3
+        uses: codecov/codecov-action@v4
         with:
-          token: ${{ secrets.CODECOV_TOKEN }}
+          token: ${{ env.CODECOV_TOKEN }}
           files: ${{ matrix.module.path }}coverage_unit.txt
           flags: ${{ matrix.module.codecov-flags }}
           fail_ci_if_error: ${{ github.repository == 'arduino/arduino-create-agent' }}