Update dependency typescript to v4

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
typescript (source)	devDependencies	major	3.9.7 -> 4.0.2

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Release Notes

Microsoft/TypeScript

### [`v4.0.2`](https://togithub.com/Microsoft/TypeScript/releases/v4.0.2) [Compare Source](https://togithub.com/Microsoft/TypeScript/compare/v3.9.7...v4.0.2) For release notes, check out the [release announcement](https://devblogs.microsoft.com/typescript/announcing-typescript-4-0-rc/). For the complete list of fixed issues, check out the - [fixed issues query for Typescript v4.0.0 (Beta)](https://togithub.com/Microsoft/TypeScript/issues?utf8=%E2%9C%93&q=is%3Aissue+milestone%3A%22TypeScript+4.0.0%22+is%3Aclosed+). - [fixed issues query for Typescript v4.0.1 (RC)](https://togithub.com/Microsoft/TypeScript/issues?utf8=%E2%9C%93&q=is%3Aissue+milestone%3A%22TypeScript+4.0.1%22+is%3Aclosed+). - [fixed issues query for Typescript v4.0.2](https://togithub.com/Microsoft/TypeScript/issues?utf8=%E2%9C%93&q=is%3Aissue+milestone%3A%22TypeScript+4.0.2%22+is%3Aclosed+). Downloads are available on: - [npm](https://www.npmjs.com/package/typescript) - [Visual Studio 2017/2019](https://marketplace.visualstudio.com/items?itemName=TypeScriptTeam.TypeScript-40) ([Select new version in project options](https://togithub.com/Microsoft/TypeScript/wiki/Updating-TypeScript-in-Visual-Studio-2017)) - [NuGet package](https://www.nuget.org/packages/Microsoft.TypeScript.MSBuild)

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