Add build script

Author: Janaka-Steph

package.json

@@ -10,6 +10,9 @@
   "browserslist": [
     "last 2 versions"
   ],
+  "scripts": {
+    "build": "npx gulp bundle && npx antora antora-playbook.yml"
+  },
   "dependencies": {
     "@antora/lunr-extension": "^1.0.0-alpha.8",
     "clipboard": "^2.0.6"