chore(greenkeeper): Update rimraf to version 3.0.1.

Closes #71.

Author: greenkeeper[bot]

packages/@opticss/demo-app/package.json

@@ -62,7 +62,7 @@
     "mkdirp": "^0.5.1",
     "moo": "^0.5.0",
     "nearley": "^2.10.3",
-    "rimraf": "^2.6.2",
+    "rimraf": "^3.0.1",
     "source-map-support": "^0.5.3",
     "tslint": "^5.10.0",
     "typescript": "~3.4.4",