set phpunit version

Author: clarkeash

.travis.yml

@@ -1,22 +1,19 @@
 language: php
 
-env:
-- PHP_UNIT=7.0
-
 matrix:
   include:
   - php: 7.1
     env: ILLUMINATE_MINOR_VERSION=5 PHP_UNIT=6.0
   - php: 7.2
     env: ILLUMINATE_MINOR_VERSION=5 PHP_UNIT=6.0
   - php: 7.1
-    env: ILLUMINATE_MINOR_VERSION=6
+    env: ILLUMINATE_MINOR_VERSION=6 PHP_UNIT=7.0
   - php: 7.2
-    env: ILLUMINATE_MINOR_VERSION=6
+    env: ILLUMINATE_MINOR_VERSION=6 PHP_UNIT=7.0
   - php: 7.1
-    env: ILLUMINATE_MINOR_VERSION=7
+    env: ILLUMINATE_MINOR_VERSION=7 PHP_UNIT=7.0
   - php: 7.2
-    env: ILLUMINATE_MINOR_VERSION=7
+    env: ILLUMINATE_MINOR_VERSION=7 PHP_UNIT=7.0
 
 cache:
   directories: