Bump vm2 from 3.9.13 to 3.9.15

Bumps [vm2](https://github.com/patriksimek/vm2) from 3.9.13 to 3.9.15.
- [Release notes](https://github.com/patriksimek/vm2/releases)
- [Changelog](https://github.com/patriksimek/vm2/blob/master/CHANGELOG.md)
- [Commits](patriksimek/vm2@3.9.13...3.9.15)

---
updated-dependencies:
- dependency-name: vm2
  dependency-type: indirect
...

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