fix: Upgrade rollup to v0.52.x to fix build failures (#60)

Author: mrdtron

package.json

@@ -77,7 +77,7 @@
     "npm-run-all": "^4.0.2",
     "qunitjs": "^2.3.2",
     "rimraf": "^2.6.1",
-    "rollup": "^0.41.6",
+    "rollup": "^0.52.1",
     "rollup-plugin-babel": "^2.7.1",
     "rollup-plugin-commonjs": "^8.0.2",
     "rollup-plugin-json": "^2.1.1",