chore(package): update rollup-plugin-sourcemaps to version 0.6.2

Closes #85

Author: greenkeeper[bot]

package.json

@@ -27,7 +27,7 @@
     "nyc": "^13.3.0",
     "qunit": "^2.4.1",
     "rollup-plugin-buble": "^0.19.2",
-    "rollup-plugin-sourcemaps": "^0.4.2",
+    "rollup-plugin-sourcemaps": "^0.6.2",
     "tslint": "^5.7.0",
     "typescript": "^2.7.1"
   },