docs: make README bookmark internal links relative (cypress-io#1312)

README.md

@@ -1669,7 +1669,7 @@ and is generally aligned with [Node.js's release schedule](https://github.com/no
 
 ### Usage
 
-`github-action` command-type options such as [`install-command`](https://github.com/cypress-io/github-action#custom-install-command), [`build`](https://github.com/cypress-io/github-action#build-app), [`start`](https://github.com/cypress-io/github-action#start-server) and [`command`](https://github.com/cypress-io/github-action#custom-test-command) are executed with the runner's version of Node.js. You can use GitHub's [actions/setup-node](https://github.com/actions/setup-node) to install an explicit Node.js version into the runner.
+`github-action` command-type options such as [`install-command`](#custom-install-command), [`build`](#build-app), [`start`](#start-server) and [`command`](#custom-test-command) are executed with the runner's version of Node.js. You can use GitHub's [actions/setup-node](https://github.com/actions/setup-node) to install an explicit Node.js version into the runner.
 
 [![Node versions example](https://github.com/cypress-io/github-action/actions/workflows/example-node-versions.yml/badge.svg)](.github/workflows/example-node-versions.yml)