Block Editor: Update the Gutenberg branch used to launch Gutenberg e2e tests.

In core, you can run `tests/gutenberg/run.js` script to run the Gutenberg e2e tests
against Core with the plugin being disabled. This test ensures that the integration
of the block editor with Core is working properly.

This commit updates the Gutenberg base branch to be used for the tests to be wp/trunk
which corresponds to the latest packages that are included in Core.

See #52991.


git-svn-id: https://develop.svn.wordpress.org/trunk@51052 602fd350-edb4-49c9-b593-d223f7449a82

Author: youknowriad

tests/gutenberg/run.js

@@ -7,8 +7,7 @@ const chalk = require( 'chalk' );
 const childProcess = require( 'child_process' );
 
 // Config
-// This should be updated every time we update the WordPress packages.
-const GUTENBERG_VERSION = '@wordpress/[email protected]';
+const GUTENBERG_VERSION = 'wp/trunk';
 
 // Utils
 /**