Bump phpunit/phpunit from 6.5.0 to 6.5.14

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 6.5.0 to 6.5.14.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/6.5.14/ChangeLog-6.5.md)
- [Commits](sebastianbergmann/phpunit@6.5.0...6.5.14)

Signed-off-by: dependabot[bot] <support@github.com>

composer.json

@@ -21,7 +21,7 @@
     "monolog/monolog": "1.23",
     "macbre/monolog-utils": "^1.0",
     "tedivm/jshrink": "^1.2",
-    "phpunit/phpunit": "6.5.0"
+    "phpunit/phpunit": "6.5.14"
   },
   "require-dev": {
     "jakub-onderka/php-parallel-lint": "0.9"