build: Update codecov and use token

Update codecov to the latest version and start using the org-wide token for uploads.

See https://github.com/openedx/wg-frontend/issues/179

.github/workflows/ci.yml

@@ -23,7 +23,9 @@ jobs:
     - run: make requirements
     - run: make test NPM_TESTS=build
     - run: make test NPM_TESTS=${{ matrix.npm-test }}
-    - name: upload coverage
-      uses: codecov/codecov-action@v3
+    - name: Coverage
+      if: matrix.npm-test == 'test'
+      uses: codecov/codecov-action@v4
       with:
-        fail_ci_if_error: false
+        token: ${{ secrets.CODECOV_TOKEN }}
+        fail_ci_if_error: true