chore: windows compat (ipfs#3405)

`rm -rf` isn't a thing on windows - use the cross-platform `rimraf` module instead.

Author: achingbrain

package.json

@@ -12,14 +12,15 @@
     "tachyons": "^4.11.1"
   },
   "devDependencies": {
+    "rimraf": "^3.0.2",
     "test-ipfs-example": "^2.0.3"
   },
   "scripts": {
     "start": "react-scripts start",
     "build": "react-scripts build",
     "eject": "react-scripts eject",
     "test": "test-ipfs-example",
-    "clean": "rm -rf ./build"
+    "clean": "rimraf ./build"
   },
   "eslintConfig": {
     "extends": "react-app"