fix: make the build work in Windows (fixes #438)

package.json

@@ -24,6 +24,7 @@
     "husky": "^3.0.3",
     "jsonlint": "^1.6.3",
     "mocha": "^6.2.0",
+    "rimraf": "^3.0.0",
     "semantic-release": "^15.13.19"
   },
   "engines": {
@@ -50,12 +51,12 @@
     "url": "https://github.com/gajus/eslint-plugin-flowtype"
   },
   "scripts": {
-    "build": "rm -fr ./dist && babel ./src --out-dir ./dist --copy-files",
+    "build": "rimraf ./dist && babel ./src --out-dir ./dist --copy-files",
     "check-docs": "babel-node ./src/bin/checkDocs",
     "check-tests": "babel-node ./src/bin/checkTests",
     "create-readme": "gitdown ./.README/README.md --output-file ./README.md && npm run documentation-add-assertions",
     "documentation-add-assertions": "babel-node ./src/bin/addAssertions",
-    "format-json": "jsonlint --sort-keys --in-place --indent '  ' ./src/configs/recommended.json && echo '' >> ./src/configs/recommended.json",
+    "format-json": "jsonlint --sort-keys --in-place --indent \"  \" ./src/configs/recommended.json",
     "lint": "eslint ./src ./tests",
     "test": "mocha --require babel-core/register ./tests/rules/index.js"
   },