Remove typings-tester and the index.d.ts test

Author: timdorr

package-lock.json

@@ -89,8 +89,7 @@
     "rollup-plugin-terser": "^5.1.1",
     "rollup-plugin-typescript2": "^0.24.0",
     "rxjs": "^6.5.2",
-    "typescript": "^3.5.3",
-    "typings-tester": "^0.3.2"
+    "typescript": "^3.5.3"
   },
   "npmName": "redux",
   "npmFileMap": [