fix homepage

Author: cherylqian

package.json

@@ -2,7 +2,7 @@
   "name": "siggraph-website",
   "version": "0.1.0",
   "private": true,
-  "homepage": "https://cherylqian.github.io/siggraph-website/",
+  "homepage": "https://cherylqian.github.io/siggraph-website",
   "dependencies": {
     "bootstrap": "^4.1.3",
     "gh-pages": "^2.0.0",
@@ -17,7 +17,7 @@
     "slick-carousel": "^1.8.1"
   },
   "scripts": {
-    "predeploy": "yarn build",
+    "predeploy": "npm run build",
     "deploy": "gh-pages -d build",
     "start": "react-scripts start",
     "build": "react-scripts build",