Update broken link for MacOS Catalina guide in README.md (#8032)

Co-authored-by: Linchenn <40653845+Linchenn@users.noreply.github.com>

tfjs-node/README.md

@@ -52,7 +52,7 @@ If you do not have Xcode setup on your machine, please run the following command
 ```sh
 $ xcode-select --install
 ```
-For Mac OS Catalina please follow [this guide](/~https://github.com/nodejs/node-gyp/blob/master/macOS_Catalina.md#installing-node-gyp-using-the-xcode-command-line-tools-via-manual-download) to install node-gyp.
+For Mac OS Catalina please follow [this guide](/~https://github.com/nodejs/node-gyp/tree/main#on-macos) to install node-gyp.
 
 After that operation completes, re-run `yarn add` or `npm install` for the `@tensorflow/tfjs-node` package.