Build/Test Tools: Update GitHub CLI fork command in README.md.

This resolves an error when running the documented command as of GitHub CLI 2.88.0:
{{{
the `--remote` flag is unsupported when a repository argument is provided.
}}}

Reference: [cli/cli#12375 GitHub CLI: fix: error when --remote flag used with repo argument].

Follow-up to [61202].

Props mkrndmane, khokansardar.
Fixes #65542.

git-svn-id: https://develop.svn.wordpress.org/trunk@62569 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

README.md

@@ -41,7 +41,7 @@ You can get started using the local development environment with these steps:
 1. Add the origin repo as an `upstream` remote via `git remote add upstream https://github.com/WordPress/wordpress-develop.git`.
 1. Then you can keep your branches up to date via `git pull --ff upstream trunk`, for example.
 
-Alternatively, if you have the [GitHub CLI](https://cli.github.com/) installed, you can simply run `gh repo fork WordPress/wordpress-develop --clone --remote` ([docs](https://cli.github.com/manual/gh_repo_fork)). This command will:
+Alternatively, if you have the [GitHub CLI](https://cli.github.com/) installed, you can simply run `gh repo fork WordPress/wordpress-develop --clone` ([docs](https://cli.github.com/manual/gh_repo_fork)). This command will:
 1. Fork the repository to your account (use the `--org` flag to clone into an organization).
 1. Clone the repository to your machine. 
 1. Add `WordPress/wordpress-develop` as `upstream` and set it to the default `remote` repository