Bumps [truffle](https://github.com/trufflesuite/truffle) from 5.0.39 to 5.0.40.
- [Release notes](https://github.com/trufflesuite/truffle/releases)
- [Commits](https://github.com/trufflesuite/truffle/compare/truffle@5.0.39...truffle@5.0.40)

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