chore(package): update rollup-plugin-typescript2 to version 0.18.0

Closes #7

Author: greenkeeper[bot]

package.json

@@ -114,7 +114,7 @@
     "rollup-plugin-commonjs": "^9.0.0",
     "rollup-plugin-node-resolve": "^3.0.0",
     "rollup-plugin-sourcemaps": "^0.4.2",
-    "rollup-plugin-typescript2": "^0.12.0",
+    "rollup-plugin-typescript2": "^0.18.0",
     "rxjs": "^5.5.6",
     "rxjs-marbles": "^2.3.1",
     "semantic-release": "^15.0.0",