build: remove yarn from package.json scripts

Author: jankoritak

package.json

@@ -19,8 +19,8 @@
     "tsc:watch": "tsc --watch",
     "build": "rollup -c",
     "start": "rollup -c -w",
-    "prepare": "yarn run build",
-    "predeploy": "cd example && yarn install && yarn run build",
+    "prepare": "npm run build",
+    "predeploy": "cd example && npm install && npm run build",
     "deploy": "gh-pages -d example/build"
   },
   "dependencies": {