Run tests on PHP 7.4 and simplify test matrix

Author: SimonFrings

.travis.yml

@@ -1,18 +1,26 @@
 language: php
 
-php:
-  - 5.3
-  - 5.4
-  - 5.5
-  - 5.6
-  - 7.0
-  - hhvm
+# lock distro so new future defaults will not break the build
+dist: trusty
 
-before_install:
-  - composer self-update
+jobs:
+  include:
+    - php: 5.3
+      dist: precise
+    - php: 5.4
+    - php: 5.5
+    - php: 5.6
+    - php: 7.0
+    - php: 7.1
+    - php: 7.2
+    - php: 7.3
+    - php: 7.4
+    - php: hhvm-3.18
+  allow_failures:
+    - php: hhvm-3.18
 
 install:
-  - composer install --prefer-source
+  - composer install
 
 script:
   - vendor/bin/phpunit --coverage-text