chore(package): update rollup to version 1.15.5

Closes #6

Author: greenkeeper[bot]

package.json

@@ -47,7 +47,7 @@
     "karma-jasmine": "^1.1.2",
     "karma-typescript": "^3.0.13",
     "rimraf": "^2.6.1",
-    "rollup": "^0.64.1",
+    "rollup": "^1.15.5",
     "rollup-plugin-typescript2": "^0.16.1",
     "rollup-plugin-uglify": "^4.0.0",
     "standard-version": "^4.4.0",