Upgrade to rollup 1.25.1 for build (ezolenko#184)

Author: marijnh

package.json

@@ -54,7 +54,7 @@
     "lodash": "4.17.15",
     "object-hash": "1.3.1",
     "rimraf": "3.0.0",
-    "rollup": "^1.20.3 ",
+    "rollup": "^1.25.1 ",
     "rollup-plugin-commonjs": "10.1.0",
     "rollup-plugin-node-resolve": "5.2.0",
     "rollup-plugin-re": "1.0.7",