docs: link VS Code badge to Marketplace

Author: manojmallick

README.md

@@ -25,7 +25,7 @@
 [![Docs](https://img.shields.io/badge/docs-live-7c6af7?logo=github-pages)](https://manojmallick.github.io/sigmap)
 [![Changelog](https://img.shields.io/badge/changelog-CHANGELOG.md-blue)](CHANGELOG.md)
 [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](CONTRIBUTING.md)
-[![VS Code](https://img.shields.io/badge/VS%20Code-extension-0078d4?logo=visual-studio-code)](vscode-extension/)
+[![VS Code](https://img.shields.io/badge/VS%20Code-extension-0078d4?logo=visual-studio-code)](https://marketplace.visualstudio.com/items?itemName=manojmallick.sigmap)
 
 </div>