tools: update dependencies in lint-md-cli-rollup

Summary
+ Update `@zeit/ncc` to `^0.16.1` from `^0.15.2`
+ Update `unified-engine` to `^6.0.1` from `^5.1.0`
+ Run `npm audit fix`
+ Run `npm run build-node`

Refs:
+ https://github.com/unifiedjs/unified-engine/releases/tag/6.0.0
+ https://github.com/unifiedjs/unified-engine/releases/tag/6.0.1
+ https://github.com/zeit/ncc/releases/tag/0.16.0
+ https://github.com/zeit/ncc/releases/tag/0.16.1

PR-URL: #26889
Refs: https://github.com/unifiedjs/unified-engine/releases/tag/6.0.0
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Signed-off-by: Beth Griggs <Bethany.Griggs@uk.ibm.com>