Update rollup to the latest version

Author: Avaq

package.json

@@ -32,7 +32,7 @@
     "c8": "^7.1.0",
     "codecov": "^3.2.0",
     "oletus": "^3.0.0",
-    "rollup": "^1.21.4",
+    "rollup": "^2.0.0",
     "sanctuary-scripts": "^3.1.1"
   }
 }