Move all task dependencies to suggestions

[hussainweb]

We require the following dependencies:

        "dealerdirect/phpcodesniffer-composer-installer": "*",
        "drupal/coder": "^8.3.7",
        "friendsoftwig/twigcs": "^4.0 || ^5.0 || ^6.0",
        "php-parallel-lint/php-parallel-lint": "^1.2",
        "phpcompatibility/php-compatibility": "^9.0",
        "phpmd/phpmd": "^2.8",
        "sebastian/phpcpd": "^3.0 || ^4.0 || ^5.0 || ^6.0"

There is always a possibility that these dependencies could introduce conflicts in some projects. Consider moving them to composer.json suggested rather than require so that the dependencies are not locked.

The problem is if we remove all the dependencies, then our default grumphp config will fail. We will need to make it clear in the documentation that the user is responsible for installing the relevant packages.

[rajeshreeputra]

I believe there shouldn't be any issues since Composer is designed to work in various scenarios. In case of conflicts, users can always download the other allowed version.

Note: updated comment

[hussainweb]

@rajeshreeputra, I am not able to figure out what are you advocating for. Are you saying we should keep the dependencies in require or not?