build: Update @types/node requirement to ^9.4.0 (#15)
build: Update @types/node requirement to ^9.4.0 (#15)

Updates the requirements on [@types/node](https://github.com/DefinitelyTyped/DefinitelyTyped) to permit the latest version.
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits)
stryker-mutator/stryker-badge,stryker-mutator/stryker-badge,stryker-mutator/stryker-badge,stryker-mutator/stryker-badge