[INTERNAL] updated phpunit version

Makefile

@@ -97,4 +97,4 @@ run-ps-for-tests:
 	docker network create prestashop-net-1.7.8-7.4
 	docker run -ti --name some-mysql-1.7.8-7.4 --network prestashop-net-1.7.8-7.4 -e MYSQL_ROOT_PASSWORD=admin -e MYSQL_DATABASE=prestashop -p 3307:3306 -d mysql:5.7
 	docker run -ti -v $(ROOT_DIR):/var/www/html/modules/mollie -v $(ROOT_DIR)/.docker/php/php.ini:/usr/local/etc/php/conf.d/custom-php.ini --name some-prestashop-1.7.8-7.4 --network prestashop-net-1.7.8-7.4 -e DB_SERVER=some-mysql-1.7.8-7.4 -e PS_INSTALL_AUTO=1 -e DB_NAME=prestashop -e PS_DOMAIN=localhost:8080 -e PS_FOLDER_ADMIN=admin1 -p 8080:80 -d prestashop/prestashop:1.7.8-7.4
-	docker exec -i some-prestashop-1.7.8-7.4 sh -c "cd /var/www/html/modules/mollie && php vendor/bin/phpunit -c phpunit.xml"
+	docker exec -i some-prestashop-1.7.8-7.4 sh -c "cd /var/www/html/modules/mollie && php vendor/bin/phpunit -c tests/phpunit.xml"

composer.json

@@ -29,7 +29,7 @@
     "require-dev": {
         "invertus/prestashop-models": "^1.0",
         "prestashop/php-dev-tools": "*",
-        "phpunit/phpunit": "~5.7",
+        "phpunit/phpunit": "^7.5",
         "friendsofphp/php-cs-fixer": "^2.19"
     },
     "autoload-dev": {