Update .travis.yml

.travis.yml

@@ -5,10 +5,9 @@ before_script:
 install:
   - composer require --dev phpunit/phpunit ^5.7
   - phpunit --version
+  - $TRAVIS_BUILD_DIR/vendor/bin/phpunit --version
+  - TRAVIS_BUILD_DIR/phpunit --version
 language: php
 php:
-  - '5.5'
-  - '5.6'
   - '7.0'
-  - nightly
 after_failure: "cat /tmp/icehrm.test.log"