chore(package): update rollup-plugin-terser to version 6.0.1

Closes #255

Author: greenkeeper[bot]

package.json

@@ -72,7 +72,7 @@
         "rollup-plugin-babel": "^4.3.3",
         "rollup-plugin-commonjs": "^10.0.1",
         "rollup-plugin-node-resolve": "^5.2.0",
-        "rollup-plugin-terser": "^5.1.1"
+        "rollup-plugin-terser": "^6.0.1"
     },
     "lint-staged": {
         "*.{js,json,css}": [