Merge pull request php-curl-class#376 from zachborboa/trusty

Use Trusty Tahr for continuous integration tests

Author: zachborboa

.travis.yml

@@ -5,16 +5,23 @@ matrix:
     - php: nightly
   include:
     - php: 5.3
+      dist: precise
     - php: 5.4
+      dist: trusty
     - php: 5.5
+      dist: trusty
     - php: 5.6
+      dist: trusty
     - php: 7.0
+      dist: trusty
     - php: 7.1
+      dist: trusty
     - php: hhvm
       dist: trusty
     - php: hhvm-nightly
       dist: trusty
     - php: nightly
+      dist: trusty
 
 before_script:
   - bash tests/before_script.sh