chore(deps): Bump mysql2 from 3.6.3 to 3.15.2 in /examples/node-mysql2

Bumps [mysql2](https://github.com/sidorares/node-mysql2) from 3.6.3 to 3.15.2.
- [Release notes](https://github.com/sidorares/node-mysql2/releases)
- [Changelog](https://github.com/sidorares/node-mysql2/blob/master/Changelog.md)
- [Commits](sidorares/node-mysql2@v3.6.3...v3.15.2)

---
updated-dependencies:
- dependency-name: mysql2
  dependency-version: 3.15.2
  dependency-type: indirect
...

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

Author: dependabot[bot]