Upgrade to codecov-action@v4 and use token

Used token from codecov.io (for rust-ndarray org).

Author: bluss

.github/workflows/ci.yml

@@ -92,6 +92,8 @@ jobs:
       - name: Generate code coverage
         run: cargo tarpaulin --verbose --all-features --workspace --timeout 120 --out Xml
       - name: Upload to codecov.io
-        uses: codecov/codecov-action@v1
+        uses: codecov/codecov-action@v4
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
         with:
           fail_ci_if_error: true