update dependencies

Author: joshbruce

composer.json

@@ -11,7 +11,7 @@
   ],
   "require": {
     "php": "~7.0",
-    "8fold/php-shoop-shelf": "~0.5.0",
+    "8fold/php-shoop-shelf": "~0.6.1",
     "8fold/php-html-spec": "~0.0.2",
     "8fold/commonmark-abbreviations": "~1.0",
     "8fold/commonmark-accordions": "~1.0",
@@ -34,5 +34,6 @@
   "config": {
     "preferred-install": "dist"
   },
+  "minimum-stability": "beta",
 	"prefer-stable": true
 }