Update dependency rollup to v1.16.6

Author: renovate-bot

package.json

@@ -20,7 +20,7 @@
     "karma-safaritechpreview-launcher": "2.0.2",
     "mocha": "6.1.4",
     "prettier": "1.18.2",
-    "rollup": "1.16.2"
+    "rollup": "1.16.6"
   },
   "repository": {
     "type": "git",