Merge pull request #57 from GrahamCampbell/patch-1

Fixed travis config

Author: barryvdh

.travis.yml

@@ -1,25 +1,26 @@
 language: php
 
-php:
-  - 7.1
-  - 7.2
-  - 7.3
-
-# This triggers builds to run on the new TravisCI infrastructure.
-# See: http://docs.travis-ci.com/user/workers/container-based-infrastructure/
-sudo: false
-
-## Cache composer
-cache:
-  directories:
-    - $HOME/.composer/cache
-
 matrix:
   include:
-    - php: 7.1
+    - php: 5.5.9
+      dist: trusty
       env: 'COMPOSER_FLAGS="--prefer-stable --prefer-lowest"'
+    - php: 5.5
+      dist: trusty
+    - php: 5.6
+      dist: xenial
+    - php: 7.0
+      dist: xenial
+    - php: 7.1
+      dist: bionic
+    - php: 7.2
+      dist: bionic
+    - php: 7.3
+      dist: bionic
+    - php: 7.4
+      dist: bionic
 
-before_script:
+install:
   - travis_retry composer update ${COMPOSER_FLAGS}
 
 script: