Bump codecov/codecov-action from 3 to 4 (#355)

Author: dependabot[bot]

.github/workflows/CI.yml

@@ -52,6 +52,8 @@ jobs:
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v3
+      - uses: codecov/codecov-action@v5
         with:
-          file: lcov.info
+          files: lcov.info
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}