Bump typescript from 3.9.7 to 4.0.2 (#271)

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)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package-lock.json

@@ -74,6 +74,6 @@
     "rollup-plugin-terser": "^7.0.0",
     "rollup-plugin-typescript2": "^0.27.0",
     "sinon": "^9.0.1",
-    "typescript": "^3.6.4"
+    "typescript": "^4.0.2"
   }
 }