add asynciterable to tsconfig

Author: Jan Lohage

types/tsconfig.json

@@ -1,7 +1,10 @@
 {
   "compilerOptions": {
     "module": "commonjs",
-    "lib": ["es6"],
+    "lib": [
+      "es6",
+      "esnext.asynciterable"
+    ],
     "noImplicitAny": true,
     "noImplicitThis": true,
     "strictNullChecks": true,
@@ -14,4 +17,4 @@
       ]
     }
   }
-}
+}