stick with phpunit in require-dev, for IDE use and to lessen complications with reflection-* deps

Author: ashnazg

.travis.yml

@@ -12,7 +12,6 @@ matrix:
 install:
   - travis_retry composer install --no-interaction --prefer-dist --optimize-autoloader
   - travis_retry wget https://phar.io/releases/phive.phar
-  - travis_retry composer require --dev phpunit/phpunit # cannot trust phpunit.phar, because this package is itself in that phar..."
 
 script:
   - ./vendor/bin/phpunit --no-coverage

composer.json

@@ -22,5 +22,8 @@
         "branch-alias": {
           "dev-master": "1.0.x-dev"
         }
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^6.5"
     }
 }