chore(package): update rollup to version 2.10.9

Closes #98

Author: greenkeeper[bot]

package.json

@@ -50,7 +50,7 @@
         "deep-extend": "0.6.0",
         "del-cli": "^3.0.0",
         "jest": "^24.7.1",
-        "rollup": "^1.19.2",
+        "rollup": "^2.10.9",
         "rollup-plugin-typescript": "^1.0.1",
         "rollup-plugin-uglify": "^6.0.1",
         "ts-jest": "^24.0.0",