Bump typescript from 3.9.7 to 4.0.3 (#130)

Bumps [typescript](https://github.com/Microsoft/TypeScript) from 3.9.7 to 4.0.3.
- [Release notes](https://github.com/Microsoft/TypeScript/releases)
- [Commits](microsoft/TypeScript@v3.9.7...v4.0.3)

Signed-off-by: dependabot-preview[bot] <[email protected]>

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

Author: dependabot-preview[bot]

package.json

@@ -78,7 +78,7 @@
     "react-test-renderer": "^16.0.0",
     "tslint-config-prettier": "^1.17.0",
     "tslint-react": "^5.0.0",
-    "typescript": "3.x"
+    "typescript": "4.x"
   },
   "dependencies": {
     "babel-runtime": "6.x",