Bump typescript from 3.1.1 to 4.0.2

Bumps [typescript](https://github.com/Microsoft/TypeScript) from 3.1.1 to 4.0.2.
- [Release notes](https://github.com/Microsoft/TypeScript/releases)
- [Commits](microsoft/TypeScript@v3.1.1...v4.0.2)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package-lock.json

@@ -62,7 +62,7 @@
     "remap-istanbul": "^0.12.0",
     "simple-mock": "^0.8.0",
     "tslint": "^5.8.0",
-    "typescript": "^3.1.1"
+    "typescript": "^4.0.2"
   },
   "optionalDependencies": {
     "ioredis": "^4.6.3"