fix(npm): change prepack script to prepare (#183)

diff --git a/.npm-scripts/prepack.js b/.npm-scripts/prepare.js
similarity index 100%
rename from .npm-scripts/prepack.js
rename to .npm-scripts/prepare.js
diff --git a/package.json b/package.json
index d6b4664..0a3e219 100644
--- a/package.json
+++ b/package.json
@@ -14,7 +14,7 @@
   ],
   "scripts": {
     "lint": "eslint .",
-    "prepack": "node .npm-scripts/prepack.js",
+    "prepare": "node .npm-scripts/prepare.js",
     "test": "npm run lint && npm run test:coverage",
     "test:coverage": "nyc npm run test:unit",
     "test:unit": "jasmine --config=tests/spec/unit.json"