Update dependency typescript to v3.9.7

Author: renovate-bot

package-lock.json

@@ -63,7 +63,7 @@
     "tsickle": "0.34.3",
     "tslib": "1.9.3",
     "tslint": "5.16.0",
-    "typescript": "3.2.4"
+    "typescript": "3.9.7"
   },
   "release": {
     "pkgRoot": "dist/reactive-forms-annotations"