Configure GrumPHP in your Magento 2 to check: Composer, PHPCS, PHPMD, PHPCSFixer, PHPCPD, PHPLint, Security Checker, XML Lint.

GrumPHP-Magento2.md

Install GrumPHP in your Magento 2

Create the grumphp.yml in the root folder of your project and run these commands below:

    composer require "phpro/grumphp:^0.14" --dev
    composer require nlubisch/grumphp-easycodingstandard --dev
    composer require wearejust/grumphp-extra-tasks --dev
    composer require jakub-onderka/php-parallel-lint --dev   

grumphp.yml

parameters:
    magento_dir: .
    bin_dir: "./vendor/bin"
    stop_on_failure: false
    ignore_unstaged_changes: false
    hide_circumvention_tip: false
    process_async_limit: 10
    process_async_wait: 1000
    process_timeout: 60
    tasks:
    composer:
        no_check_all: false
    git_blacklist:
        keywords:
        - "die"
        - "var_dump("
        - "exit"
        - "console.log("
        - "ObjectManager::getInstance"
        – “<<<<<<<"
        – "======="
        triggered_by: ['php', 'phtml', 'js']
    phpdoc: ~
    phpversion:
        project: '7.2'
    phplint:
        triggered_by: ['php', 'phtml']
    ecs:
        whitelist_patterns:
        - app/code
        - app/design
        fix: true
    xmllint: ~
    extensions:
        - Wearejust\GrumPHPExtra\Extension\Loader
        - NLubisch\GrumPHP\Extension

I have written a detailed ruleset for Magento 2. Hope it helps:
https://adapttive.com/blog/grumphp-in-magento-2