Fix dependendcy on hierarchical-cache (#149)

* Fix dependendcy on hierarchical-cache

All adapters which use cache/hierarchical-cache use "^0.4", except this void adapter makes it unable to install

* Update composer.json

Author: lunetics

composer.json

@@ -28,7 +28,7 @@
         "psr/cache":                "^1.0",
         "psr/simple-cache":         "^1.0",
         "cache/adapter-common":     "^0.4",
-        "cache/hierarchical-cache": "^0.3"
+        "cache/hierarchical-cache": "^0.4"
     },
     "require-dev":       {
         "phpunit/phpunit":         "^4.0 || ^5.1",