Update to latest version of hierarchy (#87)

Author: Nyholm

composer.json

@@ -29,7 +29,7 @@
         "psr/cache":                "^1.0",
         "cache/adapter-common":     "^0.3",
         "cache/taggable-cache":     "^0.4",
-        "cache/hierarchical-cache": "^0.2"
+        "cache/hierarchical-cache": "^0.3"
     },
     "require-dev":       {
         "phpunit/phpunit":         "^4.0 || ^5.1",