Composer: prevent a lock file from being created (#65359)

Composer 1.10.0 introduced a `lock` config option, which, when set to `false` will prevent a `composer.lock` file from being created and will ignore it when one exists.

This is a useful option for packages like Gutenberg where the `lock` file has no meaning.

It also makes life more straight-forward for contributors as they don't have to remember that for this repo they should use `composer update` instead of `composer install`. Both will now work the same.

Refs:
https://getcomposer.org/doc/06-config.md#lock

Co-authored-by: jrfnl <jrf@git.wordpress.org>
Co-authored-by: desrosj <desrosj@git.wordpress.org>

composer.json

@@ -23,7 +23,8 @@
 		"allow-plugins": {
 			"dealerdirect/phpcodesniffer-composer-installer": true,
 			"composer/installers": true
-		}
+		},
+		"lock": false
 	},
 	"require-dev": {
 		"phpcompatibility/phpcompatibility-wp": "^2.1.3",