add PHP 7.1 and PHP 7.2 build jobs

Author: xabbuh

.travis.yml

@@ -11,20 +11,25 @@ php:
   - 5.5
   - 5.6
   - 7.0
+  - 7.1
   - hhvm
 
 matrix:
   fast_finish: true
   include:
     - php: 5.3
-      env: deps="low"
+      dist: precise
+      env: COMPOSER_OPTIONS="--prefer-lowest --prefer-stable"
+    - php: 7.2
+      env: deps="high"
 
 before_install:
   - if [[ "$TRAVIS_PHP_VERSION" != "hhvm" ]]; then phpenv config-rm xdebug.ini; fi
   - composer self-update
 
 install:
-  - if [[ "$deps" = "low" ]]; then composer update --prefer-lowest; else composer install; fi
+  - if [ "$deps" = "high" ]; then composer config minimum-stability dev; fi
+  - composer update $COMPOSER_OPTIONS
 
 script:
   - php validate.php

composer.json

@@ -12,7 +12,7 @@
         }
     ],
     "require": {
-        "php": ">=5.3.0"
+        "php": "^5.3 || ^7.0"
     },
     "autoload": {
         "psr-4": {