Bump typescript from 3.9.7 to 4.0.2 (#276)

Bumps [typescript](https://github.com/Microsoft/TypeScript) from 3.9.7 to 4.0.2.
- [Release notes](https://github.com/Microsoft/TypeScript/releases)
- [Commits](microsoft/TypeScript@v3.9.7...v4.0.2)

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Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

package.json

@@ -57,7 +57,7 @@
     "react": "^16.0.0",
     "react-dom": "^16.0.0",
     "sinon": "^9.0.2",
-    "typescript": "^3.7.2",
+    "typescript": "^4.0.2",
     "vinyl-fs": "^3.0.3"
   },
   "dependencies": {