Update collections.json (#158)

Author: RustoMCSpit

data/collections.json

@@ -23,6 +23,11 @@
     "name": "OpenAV",
     "url": "https://openavproductions.com/",
     "description": "collection of instruments, effects, and development tool kits for Linux."
+  },
+    {
+    "name": "Open Audio Stack",
+    "url": "https://github.com/open-audio-stack",
+    "description": "audio plugin management software, registry of StudioRack, OwlPlug, etc."
   },
   {
     "name": "SFZ Instruments",