Set min stability to stable

Author: ilijastuden

composer.json

@@ -3,7 +3,6 @@
     "type": "library",
     "description": "Authenticate user",
     "license": "MIT",
-    "prefer-stable": true,
     "keywords": [
         "authentication",
         "activecollab"
@@ -24,10 +23,10 @@
     },
     "require-dev": {
         "fabpot/php-cs-fixer": "^1.0",
-        "phpunit/phpunit": "~5",
+        "phpunit/phpunit": "^5.0",
         "slim/slim": "~3.2"
     },
-    "minimum-stability": "dev",
+    "minimum-stability": "stable",
     "autoload": {
         "psr-4": {
             "ActiveCollab\\Authentication\\": "src"