chore(package): update rollup-plugin-sourcemaps to version 0.6.1

Closes #203

Author: greenkeeper[bot]

package.json

@@ -108,7 +108,7 @@
     "rollup-plugin-json": "3.1.0",
     "rollup-plugin-node-resolve": "4.0.0",
     "rollup-plugin-replace": "2.1.0",
-    "rollup-plugin-sourcemaps": "0.4.2",
+    "rollup-plugin-sourcemaps": "0.6.1",
     "rollup-plugin-terser": "3.0.0",
     "rollup-plugin-uglify": "6.0.0",
     "shelljs": "0.8.3",