Update to PHP 7.0 min version

fetzi · fetzi · commit 454b009ae0f9 · 2017-12-19T08:39:04.000+01:00
diff --git a/composer.json b/composer.json
@@ -16,7 +16,7 @@
         }
     },
     "require": {
-        "php": ">=5.6"
+        "php": ">=7.0"
     },
     "require-dev": {
         "karriere/code-quality": "^3.0",
