ci: add phpcs test job

.gitlab-ci.yml

 include:
   - project: 'quiqqer/semantic-release'
     file: '/ci-templates/.gitlab-ci.yml'
+
+phpcs:
+  image: composer:2
+  stage: test
+  script:
+  - composer require --dev micheh/phpcs-gitlab
+  - vendor/bin/phpcs --report=full --report-\\Micheh\\PhpCodeSniffer\\Report\\Gitlab=phpcs-quality-report.json
+  artifacts:
+    reports:
+      codequality: phpcs-quality-report.json
 #stages:
 #    - lint
 #  - release