package.json: use prepare instead of prepublish

package.json

@@ -51,7 +51,7 @@
     "build": "npm run build-locales && browserify -g browserify-css src/index.js -o dist/tmp1.js && babel --presets @babel/preset-env dist/tmp1.js > dist/tmp2.js && mv dist/tmp2.js dist/openstreetbrowser.js && rm dist/tmp1.js",
     "build-locales": "for i in `ls locales/` ; do browserify locales/$i -o dist/locale-$i ; done",
     "watch": "npm run build-locales && watchify --debug -g browserify-css src/index.js -o dist/openstreetbrowser.js -v",
-    "prepublish": "npm run build",
+    "prepare": "npm run build",
     "lint": "standard src/*.js"
   },
   "devDependencies": {