Bump net-keepalive from 4.0.11 to 4.0.13

Bumps [net-keepalive](https://github.com/hertzg/node-net-keepalive) from 4.0.11 to 4.0.13.
- [Release notes](https://github.com/hertzg/node-net-keepalive/releases)
- [Changelog](https://github.com/hertzg/node-net-keepalive/blob/master/CHANGELOG.md)
- [Commits](hertzg/node-net-keepalive@v4.0.11...v4.0.13)

---
updated-dependencies:
- dependency-name: net-keepalive
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]