chore(deps): update dependency typescript to v4 (#84)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

Author: renovate[bot]

package.json

@@ -66,7 +66,7 @@
     "rimraf": "^3.0.2",
     "rollup": "^2.23.1",
     "standardx": "^5.0.0",
-    "typescript": "^3.9.7"
+    "typescript": "^4.0.0"
   },
   "files": [
     "build",