Add vercel deployment status badge

Author: nanggo

README.md

@@ -1,6 +1,6 @@
 # NANGGO's DEVLOG
 
-[![Netlify Status](https://api.netlify.com/api/v1/badges/1f313611-7793-4b18-ba44-40a92bf88443/deploy-status)](https://app.netlify.com/sites/nanggo/deploys)
+[![Netlify Status](https://api.netlify.com/api/v1/badges/1f313611-7793-4b18-ba44-40a92bf88443/deploy-status)](https://app.netlify.com/sites/nanggo/deploys) [![Vercel Status](https://img.shields.io/github/deployments/nanggo/devlog/production?label=vercel&logo=vercel&logoColor=white)](https://vercel.com/nanggo/devlog/deployments)
 
 Thanks to [Jbee](https://github.com/JaeYeopHan)  
 Powered by [gatsby-starter-bee](https://github.com/JaeYeopHan/gatsby-starter-bee)