tools: update ESLint to 6.3.0

Update ESLint to 6.3.0

PR-URL: https://github.com/nodejs/node/pull/29382


Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>