chore(package): update rollup-plugin-typescript2 to version 0.27.1

Closes #2

Author: greenkeeper[bot]

package.json

@@ -29,7 +29,7 @@
     "rollup-plugin-node-globals": "^1.2.0",
     "rollup-plugin-node-resolve": "^3.3.0",
     "rollup-plugin-replace": "^2.0.0",
-    "rollup-plugin-typescript2": "^0.12.0",
+    "rollup-plugin-typescript2": "^0.27.1",
     "typescript": "^2.8.1",
     "typescript-lit-html-plugin": "^0.2.0"
   },