GH-4: Remove PHP from Travis configuration file, as we are using Docker.

Author: ademarco

.travis.yml

@@ -1,23 +1,18 @@
 sudo: required
-language: php
 
-php:
-  - 7.3
+services:
+  - docker
 
 git:
   depth: 1
 
-services:
-- docker
-
 env:
   global:
     - DOCKER_COMPOSE_VERSION=1.22.0
   matrix:
     - COMPOSER_BOUNDARY=lowest
     - COMPOSER_BOUNDARY=highest
 
-
 before_install:
   - 'docker-compose up -d'