Add codecov token (#130)

Author: gdalle

.github/workflows/CI.yml

@@ -32,9 +32,11 @@ jobs:
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v2
+      - uses: codecov/codecov-action@v4
         with:
           files: lcov.info
+          token: ${{ secrets.CODECOV_TOKEN }}
+          fail_ci_if_error: true
   docs:
     name: Documentation
     runs-on: ubuntu-latest