Travis build config tweaks for hhvm (#600)

* Travis build config tweaks for hhvm

* Fixed typo in skipped test

* Build config fixes to speed up the build

Author: acrobat

.travis.yml

@@ -1,16 +1,25 @@
 language: php
 
+cache:
+    directories:
+        - vendor
+        - $HOME/.composer/cache
+
 php:
   - 5.5
   - 5.6
   - 7.0
   - 7.1
-  - hhvm
+
+matrix:
+  include:
+    - php: hhvm
+      dist: trusty
 
 sudo: false
 
 install:
-  - travis_retry composer install --no-interaction --prefer-source
+  - travis_retry composer install --no-interaction
 
 script:
   - vendor/bin/phpunit --verbose --coverage-text

test/Github/Tests/Api/Repository/AssetsTest.php

@@ -48,7 +48,7 @@ public function shouldCreateReleaseAsset()
     {
         if (!defined('OPENSSL_TLSEXT_SERVER_NAME') || !OPENSSL_TLSEXT_SERVER_NAME) {
             return $this->markTestSkipped(
-                'Asset upload support requires Server Name Indication. This is not supported be your PHP version.'
+                'Asset upload support requires Server Name Indication. This is not supported by your PHP version.'
             );
         }