Update leaderboard link in README.md (#654)

Signed-off-by: Harshit Singh Parihar  <harsxit04@gmail.com>

Author: Harxhit

README.md

@@ -307,7 +307,7 @@ Thanks to all the amazing people who contribute to **DevCard** 🚀
   </a>
 </p>
 
-> 🏆 **Contributor Leaderboard** — contributors are also ranked by merged PRs, issues, and open PRs in the web app at the [`/leaderboard`](https://devcard.app/leaderboard) route (`apps/web`).
+> 🏆 **Contributor Leaderboard** — contributors are also ranked by merged PRs, issues, and open PRs in the web app at the [`/leaderboard`](https://dev-card-nine.vercel.app/leaderboard) route (`apps/web`).
 
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