npmauto: bump nan from 2.14.2 to 2.15.0 in /chromium (#20113)

Bumps [nan](https://github.com/nodejs/nan) from 2.14.2 to 2.15.0.
- [Release notes](https://github.com/nodejs/nan/releases)
- [Changelog](https://github.com/nodejs/nan/blob/master/CHANGELOG.md)
- [Commits](nodejs/nan@v2.14.2...v2.15.0)

---
updated-dependencies:
- dependency-name: nan
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]