Merge pull request #7 from pressbooks/dependabot/composer/phpunit/phpunit-6.5.14

Update phpunit/phpunit requirement from 6.5.13 to 6.5.14

Author: dac514

composer.json

@@ -8,6 +8,6 @@
         "squizlabs/php_codesniffer": "3.3.2"
     },
     "require-dev": {
-        "phpunit/phpunit": "6.5.13"
+        "phpunit/phpunit": "6.5.14"
     }
 }