bump to typescript 4.0.2 (#1117)

Author: cspotcode

package-lock.json

@@ -103,7 +103,7 @@
     "semver": "^7.1.3",
     "tslint": "^6.1.0",
     "tslint-config-standard": "^9.0.0",
-    "typescript": "3.8.3",
+    "typescript": "4.0.2",
     "typescript-json-schema": "^0.42.0",
     "util.promisify": "^1.0.1"
   },