Add GitLab CI

• Different set of boxes, there isn't a 7.2 in the current series and doesn't seem like that'll changes
• Correct PHPUnit version for PHP version, as Travis handles

Fixes #2 (closed)

.gitlab-ci.yml

@@ -12,7 +12,7 @@ before_script:
 
   # install the required packages for the running CI tests
   - |
-    apt-get -yqqf install lsb-release zip unzip subversion mysql-client libicu-dev libpng-dev --fix-missing
+    apt-get -yqqf install lsb-release zip unzip subversion mysql-client libicu-dev libpng-dev bzip2 --fix-missing
 
     if [[ $(lsb_release -a) =~ "stretch" ]]; then
       apt-get -yqqf install default-libmysqlclient-dev --fix-missing