Update typescript requirement from ^2.5.3 to ^3.4.5
Update typescript requirement from ^2.5.3 to ^3.4.5

Updates the requirements on [typescript](https://github.com/Microsoft/TypeScript) to permit the latest version.
- [Release notes](https://github.com/Microsoft/TypeScript/releases)
- [Commits](https://github.com/Microsoft/TypeScript/compare/v2.5.3...v3.4.5)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
vstirbu/chai-as-typed