refactor(package): cross-platform prepare script (scripts) (#1498)

Author: ferdinando-ferreira

package.json

@@ -16,7 +16,7 @@
   "scripts": {
     "lint": "eslint bin lib test examples client-src",
     "test": "nyc --reporter lcovonly mocha --full-trace --check-leaks --exit",
-    "prepare": "(rm ssl/*.pem || true) && npm run -s transpile:index && npm run -s build:live && npm run -s build:index && npm run -s build:sockjs",
+    "prepare": "rimraf ./ssl/*.pem && npm run -s transpile:index && npm run -s build:live && npm run -s build:index && npm run -s build:sockjs",
     "transpile:index": "babel client-src/default --out-dir client --ignore *.config.js",
     "build:index": "webpack ./client-src/default/index.js -o client/index.bundle.js --color --config client-src/default/webpack.config.js",
     "build:live": "webpack ./client-src/live/index.js -o client/live.bundle.js --color --config client-src/live/webpack.config.js",
@@ -75,6 +75,7 @@
     "mocha": "^5.2.0",
     "mocha-sinon": "^2.0.0",
     "nyc": "^12.0.2",
+    "rimraf": "^2.6.2",
     "should": "^13.2.0",
     "sinon": "^6.1.5",
     "standard-version": "^4.4.0",