Remove PHP 7.2 test that doesn't work

.gitlab-ci.yml

@@ -19,14 +19,3 @@ test:7.1:
     image: php:7.1-alpine
     script:
       - phpdbg -qrr -- ./vendor/bin/phpunit --coverage-text --colors=never
-      
-test:7.2:
-    stage: test
-    before_script:
-      - sh build/docker_install.sh > /dev/null
-      - apk add --no-cache php7-phpdbg
-      - curl -sS https://getcomposer.org/installer | php
-      - php composer.phar install --ignore-platform-reqs
-    image: php:7.2-alpine
-    script:
-      - phpdbg -qrr -- ./vendor/bin/phpunit --coverage-text --colors=never